air
1>First of all make sure that this air bottle is in test,this wiil be on the side of the bottle,do not use if this is not up to date 2>Check the bottle pressure which is displayed on a gauge which is fixed to the regulator,the pressure could be to low to work the gun.Then maybe speak to the person who you bought it from,and maybe google for the operation manuel,if this marker takes battries put new ones in,turn on the gun without the air attached and check the eye settings,if the eyes are on and there is not a ball present it will not fire and you will need to find the setting to turn them off.PS be very carefull with air.