Welcome Talleyrand
Triplea is a way to play online. You’ll find a lot of info under software. Here’s a good one: http://www.axisandallies.org/forums/index.php?topic=27127.0
YG made some strategy guides you’ll find helpful here: https://www.youtube.com/watch?v=QGow98LUYl4
Scroll towards the bottom of the forums and you’ll find “find players”. You can post there to find an opponent.