I had the same problem. It has been awhile, but I'll try to remember. If your window is all the way down you are ahead of the game. If it is not You have to pull the plate off the tailgate, find the rod that releases the latch when the window is all the way down. Lay the tailgate down, then close the latches on the side so You can run, or pull, the window out. I did not support mine and it didn't break. The motor is a bear to get to, I cut the wires short so I could replace it. Pulled out the one I bought at Autozone and it was the wrong one, left instead of right (or visa versa). It looked like a POS anyway. I returned it and bought another at Checker, looked better but cheaper than stock. I asked if they had a rebuild kit instead. The girl looked it up and they had one in stock. $8 instead of $50, works great I just had to jumper the wires since I cut them too short.
If you hear your motor run, rebuild it.