Once you figure out what's going on, it's not hard at all. I assume you're having a reassembly problem.
Removing the reciever (barrel assembly) from the frame is kind of counterintuitive; you have to literally (on my gun) strike the rear of the pistol with your hand to get it to pop loose. To reassemble, insert the bolt assembly into the reciever. Now look at it from underneath--see the slot in the bolt? That's where the hammer has to go when you put the reciever back onto the frame. Once you have the hammer lined up, line up the attachment lug in the front. Push down and back, and it'll slide together--remember, it only slides a fraction of an inch to be mated. Once you've got those two together, with the hammer in the right place, the bolt will move freely. With the bolt closed all the way, insert that little hinged post on the mainspring housing up through the hole in the back of the gun. Now, the trick is to get the little dangling piece of metal up in there, which is attached to the hammer, to hit the right spot on the mainspring housing. Before you put the reciever on the frame, it might help you to look at the hammer and see what I'm talking about. You have to hold the gun vertical and shake it around a little. Try swinging the mainspring housing into place. When you feel a little bit of spring tension, right before it swings closed all the way, you've got it. Then just lock er down.
It is only hard the first couple times, then it's nothing.