You'll get different replies, but here is my way.
1. remove seat
2. remove rear grab bar cover(you may or may not have to do this one depending on if you can get to the blead screw or not
3. remove small bleader screw in top of rear heat exchanger
NOTE/FYI: all bleader screws should have a copper washer and are on top
4. get the filler neck higher, than the screw that you just took out of the rear h/exchanger.
5. remove blead screw at the 'neck' that goes into the head
6. put either a 50/50 or a 60/40 mix into the system. Do this VERY,VERY slowly so that air has a chance to excape out any blead screw. I usually put the mixture into a 'pyrex' type container so this can be done at a metered rate. Not just 'chugging' out of the gallon container. When the coolant starts to come out the rear exchanger.....put screw back in.
7. continue to SLOWLY add coolant till it's full.
8. when full, install screw in the neck at the head and put cap on.
9. run sled till all exchangers are getting warm/hot.
10. top it off.