bind kp_downarrow "exec SprayScript.cfg
Install your spray into: steamapps\common\Counter-Strike Global Offensive\csgo\materials\vgui\logos name it into spray and correct spray.vmt path with correct name.
Install script into steamapps\common\Counter-Strike Global Offensive\csgo\cfg with name SprayScript.cfg
When in game, you have to press kp_downarrow (keypad number 2) when you are in server. then just spray 'n play