There is a truck load to learn about income investment properties if you are not already a landlord. Due diligence, financing, operations, state landlord tenant laws, only to mention a few. Boot camp is good to understand parks, the interweb has plenty on being a landlord and your state should have the codes on line. It is mandatory that you learn the state landlord tenant codes before you invest. Give yourself 6 months to a year of studying to get your head around it. If you are already a seasoned landlord concentrate on getting to boot camp.
I suggest you join the Biggerpockets forum to get a solid understanding of managing tenants if you do not have experience. Being a landlord is high stress, hard work and long hours so be prepared. It is not a passive investment, you are starting a business.