For context, I"m not sure if you saw the latest Stacker News Live... but @Car basically said SN is full of gamblers... but "they're philosophical gamblers"
It's very easy to use. Denominated in sats. Just pick how many shares you want to buy and it will give you a lightning invoice for the amount of sats. You can also sell shares if you think you made the wrong pick.
As it stands now you will make more on Predyx with a Florida win than in the contest with a Houston win but because Houston didn't run away with it you should be able to thread the needle and earn on both if Houston wins.