First we need download some files. Linux:http://puu.sh/1ikIN Windows:http://puu.sh/1fhWu Put these files in folder where your srcds.exe exists After that you need download file that namedgmsv_mysqloo_win32.dll or linux version Link:https://github.com/FredyH/MySQLOO/releases Put it in garrysmod/lua/bin . You ready to use MySQLOO. How to use it you can find at garrysmod wiki.