Once you've established the heaviest part of the wheel and marked it, you never have to do that step again. Check out the valve stem and replace it if it looks suspicious, you can get them at any car parts dealer for next to nothing.
Put the new tire on the wheel by reversing the procedures outlined above, making sure you've got the rotation direction arrow on the tire on the correct side of the wheel.
Halfway there! Now is the time to rotate the tire to align the light spot dots with your punch marks on the wheel; once the tire is fully mounted it's almost impossible to turn it on the wheel. Use lots of lubrication!
Keep the already-mounted part of the tire bead pushed down into the depression in the center of the wheel as you dismount and mount the tires, otherwise you're asking it to stretch a LOT and they don't like doing that!
Now it's time to balance the wheel with the new tire on it. The Marc Parnes balancer comes with great instructions, so I won't reiterate them here. Suffice it to say that you find the heavy spot again, then put weights 180 degrees opposite that spot to balance the wheel. It's a trial and error business to get the proper amount of weight, so I stick them on the wheel using masking tape until I have the proper amount delineated. Make sure you've put the valve stem back in, aired up the tire to proper pressure, and put the valve cap back on since all that affects the weight distribution. (The valve stem and cap should be installed when you balance the wheel without the tire mounted yet.)
Sometimes the new tire is reluctant to seat properly until it's aired up to proper pressure. Use plenty of lubricant and DO NOT OVERINFLATE THE TIRE to get it to seat! You may have to deflate it and relube, then pump it back up to proper inflation before it seats properly. Don't get impatient, it will eventually pop into place. Don't have your finger stuck in there when it does or it will pinch it off!
Once the wheel is balanced you can gently spin it and it will stop randomly since there is no longer a heavy spot anywhere.
Install the wheel weights with double-sided foam tape. If you have several weights in one spot put them in the center of the wheel or split them evenly on the left and right sides of center.
Reinstall the wheel, torque to proper tightness:
The front wheel is the same procedure, you just have two brake discs to work around:
Now it's time to clean up your messy garage!
I like to get right out and start wearing the nubbies off!
Ride cautiously for the first 50 miles or so on your new tires as they get "scrubbed in". Manufacturers use a mold release compound in the tire construction process that takes a while to wear off and the tires won't develop their full grip until they've got a few miles on them.
I spent about 1.5 hours doing the GS tire swap and balance by myself. It will go quicker next time since I can skip the balance-the-wheel-without-the-tire step. My total investment in tools for changing and balancing is under $150. The dealer charged $230 for labor to remove, replace and balance two tires and the tires were $240. I can get a set of MEZ6's for the RT or Tourances for the GS shipped to my door for under $215, so after only one tire change I'm already saving money. Since I live in Wyoming where there are ZERO dealers and other brand shops won't mess with my wheels, it also saves me a couple of days in time (and the expense) of getting the wheels and new tires to the dealership.
I hope this helps. Now go wear those tires out! Happy trails!