This app was mentioned in 2 comments, with an average of 2.00 upvotes
Best thing to do is to jump in and play man. Random pick some heroes, watch some streams, ask questions.
If you have an Android phone, highly suggest you get the Companion app for Dota 2.
At work atm, but If you're still on in a few hours I'll shoot you a pm and we can play a match or two.
No worries. I made some edits BTW.