There is no spring on the right side of the gun. There is a similar piece WITH a spring on the left side of the gun.
-Put that little detent piece on the right side in, and fit the right safety in.
-Put the little detent piece with the spring into the similar position on the left side of the gun.
-Place the assembled sear cage down and push it down till the holes line up through the frame.
-Insert the left side safety. You will have to pull back on the little spring detent thing to get the safety all the way in.
-Push it together nice and good. Make sure the arm of the sear spring is in the groove.
-Have a beer.