You must backup your original cstrike folder.
For testing on your own server without third-party software: Open the console with the tilde (~) key. sv_cheats 1 and press Enter to enable cheat permissions. cs 16 simple wallhack extra quality
However, the "extra quality" title also comes with "extra risk." The most powerful cheats are often the most heavily detected and the most likely to be riddled with malware. You must backup your original cstrike folder