Some oil on your fork tubes...seems your oil seal are out. Check inner tube surface immediately, because a 'bump' can be the cause of the problem. If so, sand it using very soft paperglass, size 600 or 1000. Surface must be totally smooth.
Then I let you have a look on the fork oil operation page for the first steps, and then we'll come back when tubes are removed from bike (with its cap bolt untighten, of course). Here shall you face the most difficult part of the operation : untighten the allen screw which is at the bottom of fork. You have to remove this screw to split fork in 2 parts. Here is it :
The problem that can happen is that cartidge and screw turn together, and you won't untighten anything. So, if your bike has a preload setting, tighten it as much as you can. If not, try so, and ask somebody to push on the tube if that doesn't work.
Install your fork in a vice, protecting it with some wood.
Once screw has been untighten, see fork oil page to see how to remove cap bolt, spring, spacer and drain all oil. Then untighten definitely cartidge screw and remove it. Now you have an empty tube; remove dust deal with a little screwdriver (be careful !!).
Extract circlips which is just over oil seal, still using the same little screwdriver.
Now it's time to remove oil seal. Pull on the inner tube until everything dismantles. You can extract used oil seal.
Check anti friction rings surface. If there is any wear, change it, or you'll destroy your tube. When reinstalling these rings, place their space on the side of the fork (see arrow on picture), or you may scratch your tube too.
In order to improve oil seal lifetime, put some grease on its inner part.
Install it on the tube in the right position (usually marks on top). Push it as far as possible with your hands, and then, use the used seal to finish installing. Use a hammer and a piece of wood, striking on one side and the other, taking care to keep the seal right.
Then reinstall circlips, dust seal, cartidge. Place tube in vice, tighten bottom screw as much as you can. Finish putting together all parts of tube (oil, spring, etc...see fork oil page) and lock definitely allen screw. Now you just have to reinstall tubes.