Kx 125 fork!!!

Hello first of all i am new on this forum and i don't know if i am in the good section if not please advise me. I have a kx 125 2000 and my front fork's seals are finish... The one who is leaking is only the one on the bottom (last one) oil is getting out by there. I wanted to know is there a special process to take it off or i can simply take it off and put the other one there with no probleme. And if sombody know the ratio of the oil that goes in there i've looked in my book and it can't tell me. My front fork is a Pro-tech so i don't know if it's the same!!! thank you for your answers :cool:

replace seal

by the way the seal i need to change is the one we can see on the bottom

thanks but i didn't bother i bought new ones. Thanks anyways.. i've put 4 inches of oil in it?? is it enough