How to start?
I will guide you in your first use of Build:
1: Start Build; you arrived in front of a black screen. With the mouse and the space bar try to make a closed sector.
2: Put the cursor in the sector with, with right button of your mouse.
Presse ENTER of the num pad to pass in 3D.
To move the floor and the ceil put the cursor on it and presse the keys PAGEUP and PAGEDOWN.
3: To change the texture of the ceil, put the cursor on it, and press [V]. You arrived in the menu of used textures already used. press [V] a second time, and you arrived in the menu of all textures. Choose a sky texture.
4: I know it isn't very well, but it's normal. you must press [P].
5: Come to 2D mode (ENTER of num pad)
We will do a road that pass throught the level. you must insert points on the wall with the key [insert]; you can use [G] to change the size, and you can use [Q] and [W]. I advice you to save your level at each time you do something difficult.
Put the cursor where you have insert points, and hit the space bar to link them. you must see red line.
6: Passe in 3D mode.
The road is invisible, because it had the same texture than the floor; put the cursor in the sector of the road and press [V], to find the good texture. Now you see the road so you can put the cursor on it, and press [pagedown]. If tou want you can change the texture of the sides of the road.
7: Now we will build a house:
You must draw a small sector (white), put your cursor into it and press [Alt]+[S]. the sector his now red. Pass in 3D mode, put the cursor on the top of the house and you press [page up]. Put textures on the house.
8: Place sprites (objects):
You can place objects in D or 3D mode. you must press the [S] key tu put them or the [Supp] key to delete them. You can resize them with the keys 246 or 8 of the num pad.
Now you know the bases to build levels but try to do some smalls levels to know this very well, before starting to use sectors effectors (SE).