How do you install mods?

Hi, I played MTG back in the late 90's and got out in the middle of the Urza block. I downloaded the version of the computer game you guys, and am having a lot of fun with it. Thanks for your hard work.
I downloaded one of the Golder Years mods, and was wondering how exactly I use it. I tried copy pasta, and I had to reinstall the base program
I downloaded one of the Golder Years mods, and was wondering how exactly I use it. I tried copy pasta, and I had to reinstall the base program
