Here is a nice tutorial that will answer most (if not all) of your questions: http://www.wolfensteinx.com/surface/tutorials.html
It includes tutorials on the following subjects:
Beginner
Getting Started
Basic Construction
Make a Room
Compiling
Ladders
Sliding Door
Rotating Door
Damage
Sky
lights
Models
Entities
Alpha textures
Sounds
Water
Fog
pk3
Sparklies
Caulking
Glass
Intermediate/Advanced
Manipulating Brushes
Texturing
Curves & Patches
Arch (bevel method)
Arch (end cap method)
Arch (with trim around arch)
Script Mover
Hint Brushes
Easygen (terrain making)
Vaults
Bump Mapping
Caulk Hulling
Making an installer
Multiplayer Specific
Objectives - Explosive
Objectives - Documents
Objectives - Checkpoints
Singleplayer Specific
AI March Script
Creating aas Files
Script Mover
Kims AI scripting how to
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