A while back, you removed the trigger assembly and were careful not to let the hammer fly forward. In other words, you either kept the safety on and didn't pull the trigger, or else you put a hand on the hammer while you pulled the trigger, and eased the hammer forward so you could brush out the crud and cobwebs. After that, you cocked it and re-set the safety. Right? If not, do it. You can't assemble the trigger group into the receiver unless it's cocked.
Now the time has come to put the trigger assembly back onto the gun.

Put it in place, as shown in the photo. Take a look at the photo, at the rear of the action spring. See how the spring is crooked, and needs to be compressed on its bottom side to square it up? Also, look at the hole for the pin that holds the receiver in place (at rear of receiver). Notice that it's not lined up.

Now, on to the next step.