How to replace fork seal?

Angela, do you have a Clymer, Hayne, or service manual for the bike? If not you should get one, there is a lot of valuable information in there even if you don't do all the work yourself.

Replacing the fork seal requires putting the front end in the air, disconnecting everything from the front wheel (brake lines, speedometer cable if there is one), and dropping the wheel and fork tubes CAREFULLY to separate the two pieces of the fork tubes. Then grab the old seal and replace it with the new seal.

This short description is a VERY abbreviated and simplified version. It's not hard once you have done it a couple times but be very careful not to bend anything in your forks. They have springs inside them too. Change the oil while you are in there. Usually 10 or 15 weight fork oil but look in your manual. If you can't find a manual post again with your bike's year and we will see what we can come up with.