If you have experience with Arduino, this should be fairly straightforward for you, the only custom components you'll interact with from the Gizmo team in the Arduino environment is our very short library that abstracts over all the communications components to make the gamepad and field hardware look like a very large I2C peripheral.

As far as purchasing kits independently of your hub, that ordering will open Soon (TM). We're in the middle of making sure hubs have all the hardware they require and then we'll open up the floodgates for everyone else, but at the moment hubs have priority so they're able to do their own internal training and have access to Gizmos to validate this year's game over the next 3 months.

The team out of Georgia BEST has produced some excellent content up on BEST EDU which walks you through getting started. You can find that content by going here and then clicking on 'Students' and then searching for 'Gizmo'. You'll find content for both CircuitPython and Arduino. The tracks are identical and go over the same set of tasks in each language. If you have other questions, of course feel free to open threads in this forum.