• verify the coins you receive and make sure they are real coins following the rules of Bitcoin as you understand them.
• broadcast your transactions to the p2p network so they will be seen by lots of miners.

As far as devices, I'm a fan of an old laptop or computer with whatever node software you like. Core or Knots or Umbrella or Start9 -- I believe all have their software available for free.

Sounds like a great meetup!