@AntonioDeGou Welcome. A good start is to check the “Local” and “Fediverse/Global” feed or timeline, and follow people you are interested with. Then interact with them in their posts by replying or boosting/resharing their content.
Once you get the feel of the place, and once you form the kind of content you want to see, you can start creating “Lists” to filter the accounts you are following into topics.
Also watch out for @-tag to a.gup.pe and fedigroups.social (to mention a few), as those are groups. You can follow those groups and you'll receive all the posts it auto-boosts from other users. (And you can post to it by @-tagging the group account.) Groups are a great way to interact and reach more people without directly following everyone. Thus, you can keep your Following manageable.
Welcome and hope it helps!