Jack up rear of car.
Rotate wheels and check for play, if they sound rough the bearing knackered.
Remove cap in the centre of the hub to reveal the nut as shown on the haynes manual.
Wipe with a rag to remove the grease, remove the split pin, remove the nut locker, remove nut and washer, rock drum to remove bearing.
Next bit can be tough with drums, make sure the handbrake is off (duh!)
Rotate drum and pull back or off at the same time and work it off to remove drum.
Once off you will need to clean, you will se a bearing seat on both back and front, shiny thing the bearing sits into.
These will have to be tapped out with a hammer and punch.
Once out clean everything
Tap in new seat into position using a suitable socket, or round punch, ensure they are seated all the way down.
Grease up the new bearings.
Install rear bearing and then the new seal if it comes with the kit.
Push on the hub.
Install outer bearing.
Install washer and nut.
Rotate hub as you tighten the nut.
Just give the nut a slight nip, and ensure the bearing runs freely without rock.
Lock up, with split pin and reinstate cap.