I am in the middle of making several sites, that nearly all need coppermine, the problem is I don't know how to install it. I have seen the tutorials on the coppermine site but I don't get them, can anyone explain it to me?

What is your Hosting Control Panel?

If you use CPanel, you can install Coppermine through the Fantastico option.

If you use Directadmin, again it is part of Installatron.