Grenade launcher (Devil May Cry)

Recently started to pass the first DMC on a PC after the passage of the DMC Devil May Cry and faced with such a problem that the control on PC is much different. I figured out how to jump, figured out how to fight and shoot guns, but...still do not understand how to use the grenade launcher! If anyone had this problem, then can someone explain to this dumb newbie how to use it?)))