Need advice on installing a pre-hung door.

I completely hang the doors first, then remove and stain/seal the door slab on saw horses, then putty/sand/stain/seal the installed jambs. Never stain/seal the whole door slab while it is verticle, or you'll get drip marks. Hardware is pretty easy to change out, bring one of the hinges to the store and match it up size-wise as best you can. The knob is standard, so any knob will fit.

You're talking about an outside door? I'll assume so....

Your decision but I'd install and finish it. That way you can do both sides at once. If your weather conditions outside don't allow that, I'd finish it inside then install. We get some dry wind-free days here that I wouldn't hesitate to do the job outside. But in windy areas I wouldn't chance it

Changing door hardware is as easy as it looks. If you can't change door hardware you really should have a pro install your jamb.

Sorry I did not mention that this is an interior door. If I plan to comeback and install Pergo flooring, should I install the jam and set it on the floor, leave the moldings off and then cut them to fit on top of the finished floor ?

It's not just the moldings - you'll have to cut the jambs too.

Go ahead and install the door (with moldings). When you're ready for the floor, cut everything to size with a Multifunction tool.

You don't *need* a mulifunction tool, especially if you're only hanging 1 door.

Who do you think carries better pine doors ? Menards or HomeDepot ?