There is a lot of questions that you should perhaps first ask yourself as to what kind of person you are and what your favorite activities corrospond to.

What you need to know to play casino is thankfully, not a lot. The games are self explanatory or have guides/tutorials that, if you cannot find on the casino website, you can definitely find online. For the beginning, I would stick to traditional games that everyone knows like blackjack.

Casino and sports gambling games are both luck based. At this point, you should decide based on whether you enjoy sports more than for example, card games.

Fortunejack is a good platform for beginners (even though it might seem like I am biased because I am promoting it).