My suggestion would be to watch some of the rich dad / poor dad youtube videos. From there go to Morris Invest youtube videos and biggerpockets youtube videos. They are what I enjoy to watch.
You are going to want to setup an LLC but you will need to speak with lawyers and CPAs to help figure out what the best setup is. (One options is "Corporate Direct" to assist with LLC creation) Haven't tried corporate direct but I'm looking at going through them in the future to assist with re-org of my LLC.
After LLC is created get an EIN and get the business accounts created.
Rule 1 though is never have a rental property under your own name. Have it under the LLCs name. It is a form of asset protection.
Also look at all the ways you can get money / loans.
You can get a HELOC to assist with purchasing a property (Not a Home Equity Loan).
You can use companies like Fund&Grow to assist with using business credit to purchase real estate.
In my area in NC I've noticed that credit unions can have good rates for mortgages or HELOCS and will allow to pull up to 100% of the equity out of a property to go and purchase something else.
I almost bought a 4 plex a few weeks ago and decided not to after getting the inspection on it. That would have been my first property. I've learned that if your just starting out, get a single family home. Get a few Single Family Homes then try a 4 plex. Easier to build up experience as you go or you could do the trial by fire and dive all in.
Good Luck to you. Just take one step at a time and keep moving forward.