This tutorial will show you how to install skins for Half-Life 2. This might not work for all skins, some of them
require some other folder extracting, This will be showing the easy way.
1. go to your Steam Folder, which is in your program files or program files (x86) if your on a 64-Bit System.
2. Go to your steamapps folder.
3. Then go to your common folder
4. Then go to your Half Life 2 Folder.
5. Then go to "HL2" Folder
6. Create a Folder named "custom" You don't have to do this if you already have one.
7. Then download your skin and place the folder skins of whatever you downloaded into the customs folder.
8. Then it will work :D
[Note: This might not work for some skins, sometimes it will error, but Don't worry just find another skin to install or something]