The tube that holds and captures the spring has two studs on it. They go through the frame and are staked in place. This takes in many cases a special staking tool. As for the spring it has two pins, one on each end.
The spring should have a bend in it so it dose not fly out of the tube.
The pins on the spring may be different lengths, put them back the same way they came out. That is left side and right side.
You will need a gun smith to stake the new tube unless you are o k with doing it.---------------the spring and pins should work from the old loose plunger tube. The slide holder is called a slide stop, the other is a thumb safety.
Hope I helped