To install first go into the directory that you have your Steam installation and locate your counter-strike source\cstrike\models\weapons folder, for example :

C:\Program Files\Valve\Steam\SteamApps\example@somewhere.com\counter-strike source\cstrike\models\weapons

Put all model files in there.

Next choose which material type you would like from this zip, either Platbody, StainedBody, StainlessBody or TacticalBlue. I have included all 3 shell textures in this zip, so then please choose the shell type you want to use either NormalShells, BrightRedShells or BuckshotGreenShells. Navigate to your counter-strike source\cstrike\materials\models\weapons\v_models\shot_m3super90 folder, and placed the shot_m3super90 contents from the appropiate folder in the zip into this folder.

Finally, if you want the VGUI (the buy menu pic) copy the m3 vtf to

C:\Program Files\Valve\Steam\SteamApps\example@somewhere.com\counter-strike source\cstrike\materials\VGUI\gfx\VGUI

If the folders don't exist, create them.

You should now have the model installed, so go on Counter-Strike Source and start fragging :)

I hope this is understandable, if theres any questions or any confusions please private message me or try and contact me through ttl_hawk@msn.com and ill try and help you with the installation.

Thanks,
Hawk