How do i use api fungus cure for my fish?!?

I have two oscar fish in my tank. My one oscar has a white cotton fungus on its body and her fines are braking off..... I used maracide at first because I got told it was ICK it is not working! So I went out and got Fungus cure API. The directions for use sucks I cant figure it out. I want to be 100% sure on what I am doing. Please help me if you know on how to use this fungus cure API!