All I did was put the smx file in my plugins folder and it should be activated by default. If you are on csgo it might not be boosting you because of the velocity cap at 300 u/s or whatever it is.
You should do a donation drive if you are hurting for cash, if you reached out i'm sure a lot of the players here wouldn't mind donating to keep the server running.
Just get the smx file or compile the source pawn file, then put it in your plugins folder in sourcemod. Then you can call slopefix_version to see if its on your server.