Actually, it is easy to build a map. What you need is my complete videos. Each video is related to others and very essential to follow.
1. VALVE HAMMER EDITOR - SETUP
Video by: Deepeyes
Tools: Valve Hammer Editor v3.5
Difficulty: Basic
Requirement: AVI Codec
Description: Explanation and definition how to setup your editor
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2. VALVE HAMMER EDITOR - BASIC ROOM
Video by: Deepeyes
Tools: Valve Hammer Editor v3.5
Difficulty: Basic
Requirement: AVI Codec
Description: Explanation and definition how to build basic room
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3. VALVE HAMMER EDITOR - COMPILING
Video by: Deepeyes
Tools: Valve Hammer Editor v3.5
Difficulty: Basic
Requirement: AVI Codec
Description: Explanation and definition how to compile your basic room
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You can download the tools here
You can learn more tutorials here