It's very simple, drop the header pipes and unscrew the stud that's at the back closest to the starter, take off the shifter lever and just unbolt the two studs holding the starter. When installing the new one just position the inside gear close to the center and insert the new one in. You'll see the starter going all the way in when it goes into the gear.
I have heard a lot of stories of the chain and gear 'rolling' into the engine but only after I had done mine with the bike up on the center stand. I had no trouble at all, easiest thing I've ever done to bike on the side of the road. Many say if you do it on the side stand it's OK