If you don't read music, the best thing to do is to find songs you like, and then try to learn to play them by ear. If this is your first instrument, this will be challenging.

A better option would be to google for tutorials. There are lots of videos that will walk you through how to play a song note by note. They also usually integrate general advice about how to best handle the instrument.

If there are other musicians in your life, play with them as much as you can! They will help you in tons of ways, even if you are just fumbling along. Of course, you could also find a teacher, if that interests you. A teacher would make sure that you aren't developing any hard to undo bad habits.

You can also look up mandolin tabs. Tabs is a VERY simple notation system that does not require you to learn to read music. (sorry if you already know about tabs, can't tell what you do and don't know)

Last option would be to find sheet music for songs that you like and learn to play it.

If you don't know music theory already, you will eventually want to develop some knowledge. There is great debate on how soon that should happen. Some people never learn any theory, but I find it quite important. Its part of knowing how to speak the language of music. But some people just play so intuitively that they don't need it.

But most of all, play with joy for whatever sound you are making, and share music with others. I had a violin teacher once that would always remind me that we were always playing for Krishna. That is what it is for :D Listening to lots of music brings lots of inspiration too, though of course you know that :D

Ask me any questions as they come up! I monitor my replies, so that is a great way to get my attention, at least right now!