Welcome to BP! Since you’re just starting out, you need to determine what you need to accomplish from real estate investing. Meaning, if you’re looking to replace your current job with your investments, then you need to determine how much cash flow you need to earn per month. Once you have this number, then you can determine how many units you need to acquire to reach your goal.
As far as property criteria, this is solely up to you. You’ve stated you wanted to invest in SFRs and duplexes that’s a start.
How many beds/baths does must the single family have?
How much do you want the property to cash flow after expenses every month?
What return are you looking to make on your investment?
What area are you looking to invest in?
How much can you afford?
Take some time to determine the answers to all these questions.
Feel free to reach out if you have additional questions.
Keep reading, listen to podcasts, read books from the library, talk to local ppl you know who are in real estate. Figure out your goals, endgame, your why, work backwards and you will get there