seriously. it's not that big a deal. if people in gaza are still standing up to their oppressors every day then you likely have zero excuse for not doing more IRL shit (political reading and writing at home are good, but don't mean anything if you're not applying that theory as practice and then assessing the results and adjusting your practice accordingly).
An org is just a group of people that do work together and have a name. It might be a political party, it might be a group focused on a specific thing that approaches it from a socialist perspective, it might just be four people trying to figure out what they want to do but they know it should be socialist.
You join one by talking to people and asking them if you can join.
What if it's a group of people that do work together but don't have a name?
That counts as organizing but I'm not sure if it's an organization unless you can name it somehow. Seems like a necessary thing to me, eventually you've gotta call it something.
Sometimes we end up doing projects and those specific projects have names but the continuous nexus behind it does not have any recognized name.