Rear Wheel Bearing replacement

First things first .You will have to remove the lock wire retaining the sprocket.

Particularily, if you're on your own, its an idea to cable tie the rear brake on....

... because it will stop the rear wheel rotating when you wish to remove the rear wheel nut (46mm socket).

Next undo the rear axle pinch bolt (17mm socket)

Some sort of bike stand or jib makes life easier.