how do I change the module cam on a golden eagle single cam bow?

I was recently given a golden eagle single cam bow and with it i was also given what I believe to be modules to adjust draw length. I was wondering how to use these modules and how to install them/change them. Also any tips on extending draw length would be greatly appreciated. Will I have to remove the string or is it possible to do with the string on the bow? The modules are different sizes, is one better for a longer draw length? I apologize for so many questions I am new to this and would like as much info as possible.