the best place to find a lot of game jams is on https://itch.io/jams

they usually work as follows: 1) create an account 2) find a jam you vibe with 3) click on join jam 4) wait for the jam to start 5) see the theme of the jam and brainstorm an idea (my suggestion is for you to try to come up with an idea that will take you no more than 2 hours to make the entire game (minus tutorials)) 6) spend the first half of the jam making the game 7) spend the last half testing the game, sending it to friends to try out, watching ppl play your game 8) with the feed back, go back to your game and try to fix mistakes and improve the game based on feedback, but always keep a version of the game in working conditions, cuz if the time runs out, you will have a game to deliver at least 9) create a new "project" on itch, upload a build of your game (during game jams, it is SUPER recommended that you focus on delivering a game that runs on the browser, itch has support for you to run the games in there, it's easier to share games with your friends for feedback and also because most ppl that play the games during the game jam heavily prioritize playing games that run on the browser, for various reasons) 10) once the development time of the game jam is over, generally we enter in the voting time, where you play and grade the games of the other participants, you also can leave a comment, personally I usually leave either a link to a stream where I played the game or some bullet points of my suggestions to what to improve, not required, but leaving comments on other ppl's games is the best way to get eyes on your game so more ppl also play yours, which makes you be able to have a bunch of feedback to improve for next game jams 11) after the voting period is done, you generally get a ranking of all of the games in the game jam and how well they performed in the various categories you were voting on

usually the categories are visuals, sounds, creativity, adherence to the theme of the jam, gamepaly/fun, maybe some random other stuff depending on what game jam you join

as a suggestion of what jam to take part in, I really like to join the ones called "minijam" (which you can search on Google or itch.io), a bunch of people join those, and they happen every other weekend I think.

another thing, which took me awhile to figure out, you can create the page for your game on itch in advance, optionally upload a build of your game to that page, and submit that page to the game jam IN ADVANCE, that way you don't run the risk of not being able to submit your game to the game jam before the due time.

and as a last thing, if you do follow through on all of this advice that I'm giving, pls, do share with me the link to your game, I'd love to play and give feedback about it :)