They can be a little scary if you've never done it before. I always remove the regulator from the door. It's either 4 or 5 bolts plus 2 nuts on the lower window glass. Once you get the glass separated from the window, have somebody else hold the glass up towards the top of the door. This will give you more room to get the regulator assy out & it will come out the big hole in the door. You will also need to unplug the motor. You will probably need to remove the idler track. It has 2 bolts, the same as the regulator.
Now you have the regulator on the bench. CAUTION!!!!! That assy is spring loaded. Most of the time you can put a 3/8" bolt, washers & nut through the regulator & the arm. This is a must to avoid getting hurt. Once you're sure the assm will not move you can take the motor off & reinstall a different one. Do not remove the bolt untill you get the new motor bolted in place.
Put it back the same way you removed it.....Joe