Hello young Lemming.
Until you say otherwise, we will suppose you like to eat beans, to compute with Linux and to watch Star Trek.
Lemmy is a part of the fediverse which is a facinating piece puzzle of software to learn about. You absolutly don't need to to use Lemmy though... All you need to know is that there is tiny little websites called instances working together to make Lemmy. You barely notice which one you access but many lemmings will proudly tell you where you are. Each instance has its own moderation team and rules so check it before writting in a new community (equivalent of sub) and relax 'cause one mod won't ruin you experience.
Here is a first community go explore !superbowl@lemmy.world. Ask for recommandation.
Enjoy!