It is important that you know how big your map is gonna be. 3D window helps alot, but export-qbsp.bat starts the map in DP so you exactly see how big is the map. You have to have spawn point though. Youst push "e" a windows pops up, choose info_playerdeathmatch and just add entity, then drag the red thingie inside your map and browse around. Other spawns are harder a bit, I learned from a jitspoe`s tutorial and learned from other maps. Ladders basically easy too, just have to select brushes and then push "s" and then add ladder flag (mark ladder box and then add flag button you push).