As far as I’m aware. No! You’ve already made an account so just GO! When the time hits and the theme releases, make some games! And then submit your game when ready. Everything else is pretty much just for fun. You might consider doing an “I’m in” post to get excited but it’s not required. Take a look at the different parts of the website as they have useful information. The rules are important and I believe there is an FAQ somewhere. Have fun on your first LD!