Season your prime rib roast and if possible let it set in the fridge for a day or more to allow the flavor to soak in.
Now, this is where you know your smoker and how to prep it for smoking. I use an electric smoker and prefer to use apple disks for smoking all my meat.
Remove your chip holder, water bin, and racks out of your smoker and cap off your exhaust pipe if necessary.
Fire up the smoker by raising the temperature on the dial
Fill the water dish and chip holder
Place in your chips and once they start to smoke put in your water tray. I find I can get a good smoke faster by doing this method.
Once your smoker gets hot enough and a smoke place in your prime rib roast on a rack. I kept my smoker at 150-200
Roast for hours at least over 6 hours. We made the mistake of pulling it out to see if we could grill it faster to finish it off and it went up in flames, learn from our mistake don't put it on the grill!
Be sure to keep replacing your smoker chips and disks to keep the smoke going.
We smoked ours to an internal temperature of 130, so be sure to look what temperature you want for how rare you want your meat.