How do you get into this sort of stuff? "grab the src, subscribe to the lists and get to hacking!" is good but as a newbie, I would definitely need more guidance :D
OpenBSD has the best docs and really all you need to get up and going. Granted you may need to read some docs a few times, but it is all there. I got going with OpenBSD just by reading.
Install the OS, grab the src, subscribe to the lists and get to hacking!
The IRC and Matrix chats are great spots to get the low down, communities are helpful and documented.