yep there's a seal in there that runs on the surface of the flange ... I assume it's in the workshop manual but failing that it's pretty straightforward ... from memory it's something like this
raise the associated rear wheel off the ground (leave the wheel on) and put the vehicle on stands (this way you'll be able to turn the axle and cv joint to get at the bolts a bit easier) ... I'll call the bolts allen head bolts because most now are; but, check first and make sure you have the correct tool
1. pick the dirt out of the allen head bolts (of the cv joint / joint boot) to make sure your allen key gets far enough in to not chew them up
2. have a freezer bag ready to wrap around the cv joint (sticky grease attacts dirt)
3. have some cable ties or a wire hook ready to hold the axle (and cv joint) out of the way (a couple of cable ties together are handy because they can be in place before you undo anything and then you can pull them tight when the bolts are off and get the axle out of the way)
4. have some fine tie wire ready to run through a couple of bolt holes to keep the cv joint and boot together
5. undo the cv joint / boot bolts, tie the two together (while still loosely bolted to the flange is fiddlier but best), bag it and hang it up out of the way .. also try to not tilt the cv joint too much in relation to the axle
6. there'll be a blue seal hiding the circlip ... try to get it out without damaging it if you like but usually you stab it and flick it out
7. use an appropriate circlip removing tool to take out the circlip holding the flange on (if you have one of the sets with exchangeable heads you'll work out which one you need pretty soon)
8. pull the flange off the splines (sometimes a puller is necessary)
9. pry the seal out without damaging the gearbox ... sometimes you can drive a screw into the seal and use it to yank the seal out but usually you end up prying them out.
10. put in the new seal (a bit of sealant on the outside won't hurt if you did scratch up the gearbox) ... you can use a plumbing fitting the drive it in square
11. check that the flange to seal surface area is in good condition and put the flange back on
12. put the circlip back in and the blue seal (bit of sealant wont hurt)
13. lower your axle and cv joint (if you leave them tied together until you get some bolts loosely started it'll be easier)