From memory so im not 100% sure
1.remove the crown[two screws either side and a retainer ring on top]
2.remove the preload/rebound adjusters[little grub screw on the side]
3.remove the little circlips on top of the caps[dont lose these]
4.grip the slider in one hand and undo the top cap on the non rebound side with a 26mm spanner
5.pull out the spring + put it on an old cloth
6.turn the fork upside down and drain the oil into a suitable jug
7.repeat steps 4,5+6 on the other leg[while its upside down ,pump the rebound rod in and out to clear all of the oil from the rebound cartridge]
8.dont undo the nuts underneath the fork tubes .If you only want to replace the oil ,leave them in place.
9.replace the oil[sorry this is the bit im unsure of i cant remember the exact grade they recommend]
10.pour in the oil into each leg[slowly]till the level is about 40mm from the top of the stanchion[extend the stanchion fully]
11.pump the rebound rod up and down so that it fills with oil and theres no air left
12.top up to the 40mm from the top level [after pumping the rebound you will need a little more oil in that leg than the non rebound leg]
13.reassemble and dont forget those circlips
If im wrong in any of these steps feel free to amend it :?