If you have .NET Framework 3.0:
1. Run the installer (install.exe)
2. Select Install
3. Select your cstrike folder (follow the instructions on the main screen)
4. Click 'Install'
5. The installer will copy the necessary files for extraction
6. You're done!
If you don't have .NET Framework 3.0
1. Rename install to install.7z
2. Open it with the latest version of 7zip
3. Extract the folders to your cstrike folder
Comment before/after downloading and remember to seed