Dungeons and Dragons

Look into your local game cafe(s). That's the type of place that sells board games, dice, minis, but also has gaming tables and often a small food and drink counter. There are likely nights for newbies you might be able to join, to experience it live.

Watch some youtube videos of people live-playing the game you are interested in. You'll see the character players interacting with the DM, propped up mostly by their shared understanding of the game mechanics, and the individual mechanics of their characters. Keep an eye out for how things are different in combat vs out of combat.

You don't need minis or dice if you play online. E.g. there is a Discord bot called Avrae, and many small communities come together around use of that bot to play, where it handles most of the crunchy mechanics like dice rolls and modifiers and even maps. Some communities play live sessions over video chat, others play without video chat but with 5 minute turn timers, and others play asynchronously with 24 hour timers in a format called play-by-post (or pbp) where they roll the crunchy math in one channel, and then roleplay their characters' actions in another. Disboard will let you search communities who are looking for members--filter by whatever tags interest you most.

Finding a live play group to play a campaign with can be... Hard. I recommend you start by educating yourself about a system via free resources, maybe finding a game cafe to experience it in a one-shot, and try some online play, before investing too much. As you learn more, you're also more likely to encounter people looking to start or grow a group.