+1 with Justin and Ed. Also, if you haven't already pulled off the battery box/holder, that makes things go much more smoothly too.
When I pulled my transmission out this past year I left the exhaust system on, left the rear wheel on and just disconnected the drive shaft
at the U-joint with the 12 point stretch bolts (it is recommended that you replace these - use them only 1x though some people re-use them).
Make sure the bike is on a secured bike jack or on its centerstand with blocks under the engine sump to keep things steady and upright.
Take a measurement of the inside space, or gap between the frame tube and swingarm tube to help assure yourself that you have things
back close to being centered upon reassembly. I recommend that you might use something a bit more accurate than a tape measure, but you get the idea.

Remove the swingarm lock nuts and unscrew the swingarm pivot bolts. Before you put it all back together go in and clean and regrease those
swingarm bearings. I found that just loosening the rear shock absorber mounting bolts and removing the rear brake control pivot and actuating
rod allowed me to just "swing" or push the rear swingarm backward, and inserted a 2x4 wood block and bungied the whole assembly so it would not
slip out of place - gives you plenty of room to work on the transmission and remove it without having the disassemble the entire rear of the bike.
Put an oil drain pain under the driveshaft as it is likely oil will leak out - be sure to drain and replace driveshaft oil and rear drive oil when reassembling
to make sure that you have the right amount of good juice in there when you have the replacement transmission fitted.