Welcome from Colorado.
I would have to believe that an internet search and about a half an hour will get you a ton of information as to utilizing angular measurements, such as MOA. Once you understand the basic concept of how angular measurement works, and how it relates at distance, your world will really begin to open up.
There are a bunch of resources on this site, with plenty of existing threads that go deep into angular measurement theory - such as MOA vs Mil systems, so do not hesitate to play around here to get a good grasp on the information.
Looking forward to your interaction here. Again, welcome.