What we need?
- Source SDK Tool
Step one - How install Source SDK tool.
After downloading open Source SDK and wait for unpacking files.
Step two - How install MDL Decompiler.
* Download file from https://developer.valvesoftware.com/wiki/Mdldecompiler
(Hooch's fixed version of MDL Decompiler (2013) (No need to change "IDST0" to "IDST," and no more AppId error)).
* Put "MDL Decompiler Fixed.exe" in X:\Program Files (x86)\Steam\SteamApps\YOUR LOGIN\sourcesdk\bin\ep1\bin
Create a shortcut on your desktop .
Now MDL Decompiler should work