Welcome to the real estate investing world Bruce. I think it's important for you to take stock of where you are and what your goals are.
How do you plan to finance the properties? - If you have plenty of money to invest, the process is almost no-brainer. If you need to raise capital and/or create partnerships, it becomes a bit more challenging and I would suggest linking up with a mentor. I urge you to be careful about paying tens of thousands of dollars and make sure you link up with someone who has already done what you're trying to do and is currently mentoring others to do the same.
Are you hoping to own just a few rentals or do you want to be the next real estate millionaire? - It's important to understand that real estate is not a get rich quick scheme. You may only cashflow a couple of hundred dollars per house/apartment, so understanding that, you can gauge how many units you would have to own to replace your income.
It takes 30 years to pay off a mortgage following a normal amortization schedule. If you get creative you may be able to pay it off sooner, but know that with a buy and hold strategy, you are in it for the long run and you will make the most money when the property is paid off.
Definitely spend some time on here & listen to some podcasts. Going to your local REIA/meetups is a great way to connect with people in your area.
It's quite easy to buy a few properties, a bit more challenging to buy many. This is not meant to discourage you in any way. It's meant to help you set realistic goals and to hopefully point you in the right direction if you have some loftier goals.
Every millionaire started somewhere! I wish you the best of luck!