It has been a while since I did it, but it was a pain. As I recall, I reached in with a small flat screwdriver and compressed the leaf spring slightly, then rocked the blade to the side to get the small nub on the end to fit into the equally small notch in the latch. Staging the spring where it goes, but slightly away from the right side of the gun allowed everything to be approximately I the right place prior to compressing the spring. By the time I was done, I had a big pile of hair from pulling it out.
I know that you're frustrated, but slow down and think it through. You'll get it put back together. Slowing down when you type your questions would help us answer them too--you have so many typos that it's hard to understand sometimes. Just a suggestion.
CC Griff