First check in your area to see if they have CORE (center of retired executives) A group of retired people who volenteer time to help young people get started in business. You will also need to talk to a lawyer to find out the monetary advantages and risks.pp
Even if you form a company, you will have to use your personal credit until you company is established. Getting a DUNS number will assist in that task. But you must consider if you are going to be a LLC, or and S-Corp, and if someone is going to be a partner, or your business is sole proprietorship.
For purposes of protecting your personal assets, you would want to be and S-Corp, however the cost to do this may be restrictive for you. The cost varies from state to state, in my state, Illinois, it cost almost $500.
You need to consider having a good accountant and attorney as well. Learn how to evict because it will happen. Know your state laws about tenant rights, which vary from state to state.
A great website to get lot of free help on land-lording is Mrlandlord.com.