How could i use lua_openscript_cl ?

So, i want to use a script, to use my midi keyboard, to play at playable piano, but i couldn't do it at some servers, could you help me ? I really want to play on midi keyboard, on the server. ;(

Type 'lua_openscript_cl (script_name).lua' in the console where '(script_name)' is the name of the script you're wanting to load.