It sounds more like you want to create a new community on an existing instance.
Setting up a new community can be as easy as clicking the new community button and filling in the fields.
Setting up a whole instance of Lemmy (like lemmy.world, which you're on, or aussie.zone, which I'm on) is way more involved than you're probably thinking - buying a domain name, figuring out hosting, installing the Lemmy software, and a whole lot more.
I like using word association as a game. It's quick to learn, doesn't need any equipment, and it's no problem to join or leave the table whenever you like.
Try to get from some word (eg HOME) to some other word (eg SUMMIT) taking only small, obvious steps.
Each step should make a pair of terms that "obviously" fit together. They can fit together because they sound similar (HOME -> ROAM), or they are written similarly (HOME -> HOLE), or have an obviously-related meaning (HOME -> AWAY)... anything that makes sense to the group.
You can take turns around a circle. When it's your turn, you announce the next link. If anyone thinks the link isn't small enough or obvious enough, they can object and you'll need to pick a different link. Then it's the next person's turn.
You can play competitively if you like (the person to reach the target word wins) but it also works fine without announcing a winner.
In a technical context, yes, a GIF refers to a specific image format. However, plenty of people now use "gif" to mean any short soundless video loop, regardless of how that video is stored.
Check your user profile.
In the app I use, the user profile shows my own activity, and has a menu for things like "upvoted" and "downvoted".
Your app (Summit) might well do the same. Otherwise check the regular Web interface (no app).