When replacing an oil pan, I will have to remove a motor mount and jack the pan up a few inches, followed by wedging sm block by harmonic balancer. To keep it up. I have never done anything like this. Can someone tell me anything specific I do or don't need to do when doing this? Is there a chance I could mess my oil pump or sensor up?
You can raise and support the engine without using a jack by using this kind of engine support bar, which you can make yourself from lumber. You could also buy or borrow one of them.
If you put the car on ramps first, then set up the bar, disconnect the engine mount and lift the engine, you can do the whole job without a jack or jack stands, no wedges and without worries of damaging something due to jacking it.
Depending on the vehicle, the engine mount bolts might be for one-time-use, so be sure to check the published procedure and obtain new, never-installed engine mount bolts if needed. (That type is torqued into the plastic range upon installation, and if ever used again, they will eventually come loose. You'll know you have those if the procedure says something like "torque to XX ft-lb plus 1/4 turn".)
As Paulster2 said, tell us the year / make / model / engine for additional tips.