Everything in Build is either a Sector or a Sprite. Sectors in their most essential form are rooms, but most everything that isn't an item or character is made from the proper manipulation of Sectors. To make a Sector, press the space bar in 2D mode and a point and line will form. Tow that line to wherever you like, then press the spacebar again to connect it to a new point. Keep doing this until you get to your starting point. Note that "G" controls the grid size and - unless you turn the grid off completely - all Sector points and Sprites will be forced to fall onto a grid point. So change the grid to finer resolutions for close detail.

Sprites are created by pressing the S key. You'll notice if you went through the textures listing (by pressing V in 3D mode, which allows you to "paint" the item under your cross-hair with a new texture) that Build groups all of its tiles, textures and Sprites together. While this can make it confusing to find a specific texture without knowing its number, it does mean that you can use any graphic you find here for either a Sprite or a Sector texture, which lets you make some impressive visual effects. For now though, look at the first row of Sprites in the Texture listing: you'll see letters, S, M, A, L, etc.

"S" is the Sector Effector Sprite, which affects the Sector it is placed in. The others will be discussed as they become necessary.

The next important concept to understand are Lotags and Hitags. Depending on what you are creating, you'll need to use these for both Sectors and Sprites. Put simply, the usual way they work is that Lotags are a set number designation for a specific command function (making a door open, for instance) and Hitags are user defined numbers used for grouping related things (as with teleporters, in order for the game to know that 2 teleporters are connected you would give them both the same, unique hitag). This is how it often works, but there are exceptions (Door switches, in particular). Lotags and Hitags are designated in 2D mode. To give Sectors a lotag, Press T. Press H to Hitag a Sector. Press Alt-T and Alt-H to give Sprites and walls lo- and Hitags.

Some things to know

• The numeric pad's enter key switches between 2D and 3D modes.
• In 3D mode, holding the left mouse button over the thing you wish to manipulate (be it Sprite, wall, floor or ceiling) will lock control over that thing, so you can move around and still change it. This is useful when you need a better vantage point while moving ceilings and floors.
• Slopes are done using the bracket keys, but they slope according to the Sector's "1st line" designation. Use Alt-F to change this designation in either 2- or 3D mode to get the ceiling or floor to slope in the direction you want. Press Alt + a Bracket key to get slopes to match with joining Sectors in 3D mode.
• Moving a point over another point within that Sector erases the point, but never erase a Sector point-by-point or else you might corrupt your level. When erasing a Sector, always use Ctrl-Del.
• Red walls are two-sided and connect to another valid Sector. White walls are one-sided and connect to "dead" space, where no Sectors reside. To turn a Sector into valid player space, press Alt-S while over the Sector in 2D mode.
• Be sure to place a player starting point (press scroll lock at the spot where you want the player to begin), and save often, using multiple files.
• Print out and read the Build documentation.
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  Some Doors
  
  Doors are actually Sectors that connect two room Sectors, and are called "Door Sectors" for obvious reasons. Door Sectors should be made the size you want the door to be and be sure to place textures on all sides of the door and it's connecting walls.
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  Doom Style Doors: Give your door Sector a lotag of 20, then go into 3D mode and bring the ceiling of the door Sector all the way down to the floor.
  
  
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• Star Trek Doors: The so-called Star Trek door requires three door sized Sectors. The center Sector is going to be the actual door. These doors are really just two walls ending in points that slide back when activated. You have to place three points along both of the one sided walls within the middle door Sector (that is, insert the three points on both of the door Sector's walls that connect to the dead space and not the walls it shares with the other valid Sectors).The points should be on the exact same grid line as their counterparts on the opposite one sided wall. Now, move the two middle points of the six you just made so that they both meet and overlap in the exact middle of the door Sector, thus giving you two triangles touching one another in the middle of the Sector. Next, move the outer points forward along the two walls that connect the inner door Sector to the outer two door Sectors (making the triangle look like an obelisk shape). The points should be placed so that everything looks even, and will result in two small triangles in the middle of the inner Sector which border the two outer Sectors. Pick one of these small triangles (it doesn't matter which) and press T to lotag it. Give the Sector a lotag of nine. These doors must have a wedged shape end in order to work properly.
  
  Switches: There are two kinds of activation Sprites you'll need for a door at the present time - Activators (Sprite #2, the "A") and ActivatorLocked Sprites (#4, the "L"). Activators automatically open/close a door when you flip the switch connected to it. An ActivatorLocked simply locks out the spacebar function until you flip its connected switch. Once switched the door will then open upon a spacebar press. Both activators are made exactly the same way - Place the actual switch Sprite where you want it and give it a unique lotag. Place the activator in the door Sector and give it that same lotag.
  
  Other Sector effects
  
  Teleporters: Make two Sectors where your teleporters will be and place a S.E. Sprite in the middle of each. Give the S.E. a lotag of 7 and a unique hitag that the two teleporters will share.
  
  
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• Water: Places where you dive into (and out of) water are actually teleporters, but with some important rules: the surface Sector where you dive into the water and the connected water Sector must be exactly the same shape and size. Give surface Sectors a lotag of 1 and all underwater Sectors a lotag of 2. Next place a S.E. Sprite in each Sector in exactly the same spot. Give both Sprites a lotag of 7 and the same unique hitag. The rippling water texture is #336.
  
  Windows: Make a Sector connecting to two rooms where you want your window to be. Enter 3D mode. Go to the top of this Sector on either side, depending upon where you want the window, and press M to mask that open space. A stone wall will appear. Move your crosshair over this new wall and press V to access the textures, press G to go to a texture and type in 503. Press return and you should have a window. Go back to 2D mode and bring your mouse over the window wall. Press B to make it blockable, so you can't walk through it and press Ctrl-H to make it hittable so you can break it. Note that if you want a perfectly clear unbreakable window, don't mask the wall, but still make it blockable and hittable.
  
  Mirrors: Mirrors are one of the absolute proofs that foresight is best. Making a Mirror requires you to not just make the mirror Sector, but also a Sector behind the mirror of at least equal size as the area that the mirror will be reflecting . Mask the wall where you want the mirror to be, choose texture #560, then press 1 to make the wall 1-sided. Make the wall blockable and hittable. To make Duke fawn over himself, give the mirror wall a lotag of 252. Note for both Windows, mirrors and any wall needing tagging or modified: Build gives Sprites a higher priority than walls, so when tagging or changing a wall (like making it blockable for instance) make sure no Sprites are highlighted at the same time, or else you'll end up modifying the Sprite instead.
  
  
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• Lifts: Make your Sector that will be the lift and give it one of the following Lotags depending upon the starting state of the lift:16 to make just the floor lower to the next Sector height. 17 to make the floor rise. 18 to make both the floor and ceiling lower. 19 to make both the floor and ceiling raise.
  
  Sector over Sector: The best way to make a Sector over a Sector is to make the new Sector in a blank spot on the grid, then move it over the Sector of your choice. Make sure that none of the new Sector's points or walls connect with the other Sector's while you are drawing it. Note that you can have a passage connect from a lower Sector to an above Sector – just make sure to get the stairs/slopes and ceilings properly adjusted. Be aware that you can generally never see the 2 Sectors at once in 3D mode. Also, be careful when adding things to the new Sector (Sprites in particular, but sometimes even walls and new Sectors) as they may keep going into the Sector below. If this occurs, place Sprites in 3D mode if you can, or else move the whole Sector to a clear spot on the map to modify it.