Hi Andrew,
I'm a realtor in the bay area and I invest out of state.
As far as getting started, it depends on your learning style. If you are okay taking online courses, I would just go ahead and sign up for one. All of the real estate schools use the same, publicly available information. They just have different ways to teach it. I used the CE shop.
As far as brokerages, you have to join one as a new agent. The only way out of joining a brokerage is starting your own, but you can't do that until you have the credentials. The best thing to do is to call a couple realtors that work at each and ask them how they like it. I joined a newer/smaller brokerage because I wanted to work at the same brokerage as my mentor. Always ask about the commission split and support for new agents. Some people say the training at KW is great for new agents, others say it's underwhelming.
It would be really hard to get started entirely on your own. You will need to join a team, find a mentor, or have some type of agreement with an experienced agent where they help you with your transactions. Sadly, the RE exam really only covers about 10% of the job. So much of it is learned on the job and not written down anywhere.
Happy to chat more if you want, just send me a DM.