download a copy of the owner's manual or pick one up at a local gun show.

familiarize yourself with the rifle by reading the manual. field strip it and clean that sucker up with kerosine, paying particular attention to the bore, chamber and firing pin (make sure it is sliding freely in the bolt).

lubricate all moving and sliding surfaces with the exception of the front (large) gas piston...run it dry.

load one round up. hold the rifle low and away point it in a safe direction. cock and fire it. inspect the spent case for bulges, splits, tears or primer flow/piercing. if it works, load three rounds up and test fire again, still shooting from the hip. if it safely fires in a semi mode, and the spent cases look like the headspace is good...blast away and have fun.