You screw the footrest mounting bolt into the end of the primary shaft, leaving one footrest on the bolt and one nut on the end of the bolt. All you do then is slide the footrest back and fro until it hits the nut, the shaft will slide out fairly easily. Same technique as a slide hammer.
The other bearing will stay in the case, remove the oil pump and you can see a section of it, a wooden or brass drift and you can knock it out of the case quite easily.
I've reused circlips but it depends on how they come off IMO, it's best to replace them though, especially if you remove the kick starter shaft one. The gearbox ones are special having a flat side on one side so buy genuine ones for those if replacing. Unless the gearbox bearings or gears don't show wear or damage leave the box alone. Check the gear selector forks tips though which are on the gear selector drum.
It's not as hard as it looks or sounds, get stuck, ask for help.
Where is your location as a member may be near to help you out.