First property investment in Colorado

I'm new to this type of thing so any advice is welcome.

I've been told that I have to own a house for 2 years before I can rent it out or anything like that. What are they talking about exactly? I'm not looking for a house for me to live in, I'm looking for a property to rent out asap. Do I absolutely have to have the house for two years before I can rent it out or is there a way around this?

Also, I'd like to know what kinds of buyer's contracts there are in my state. I'd like to get a return on this investment as soon as possible.

Is there something I'm unaware of? I'd rather not go into this blind.