I've done it several times, and it's not really all that hard. The platform sanders make it pretty hard to screw up so long as you don't stand still with it. Here's what I would suggest:
If the finish is still there, or there's wax, use a chemical stripper first, and let it get good and dry before you sand.
Follow the directions in the brochure, and proceed through all the grades of sandpaper.
Accept the fact that it's not a new floor, and there will be defects. This is called "character".
If you're pulling up carpet, make sure all the tacks are out or you will ruin your sandpaper.
Try not to topnail too much. You'll have to set the nails, fill them, and try to get it all to match, finish-wise.
Use the water-based finish. The fumes are monstrous otherwise.
Dust well before you finish, but it's damn near impossible to have the floor completely particle free, especially if you have animals or plaster walls.
While you're sanding, open a window and put a box fan in there backwards to help suck out the dust.
All that said, I'm not a pro, so someone might know more than I. I just know what worked for me.