Take off the shift lever link and front sprocket cover. make sure you mark how the shift link comes off. Loosen the axle nut and chain tensioners all the way. You will have to push the wheel forward a bit. When you put it back on with the new sprockets, it will move back a little bit from it's original point on the swingarm.
.....Is it better to remove the front sprocket's nut, before or after removing the chain?
I'm thinking ( as if this is a car) of removing that nut while it's still "in gear", so the sprocket won't keep spinning while I'm trying to loosen that nut.
Oh, what are the torque specs on them?
Some have found it easier to remove the front sprocket before removing the chain. You can also use thee rear brake or a 2x4 laid across /under the swingarm and thru the rim. This keeps the engine from turning if the nut is too tight. Having an extra person to help is recommended.
Wheels/Tires- N·m / kgf·m/ ft·lb
Front Axle Nut- 88/ 9.0 / 65
Rear Axle Nut- 98/ 10.0 / 72