First time renting a unit

[Sonu Sundar]

Hello

I am a single person, recently bought 2200 square feet house in Dallas county and unfortunately change in job nature, led to travel frequently. So i would like to use the mother-in-law unit [part of the house] for my stay and rent 1700 square feet to a middle age or senior couple.  

This is my first attempt of renting the property.

Is it better to go through the rental agency?  or try on my own?

How do I screen the people of similar interest?

Do I need a lawyer to draft the rental contract?

Input is greatly valuable.

Thank you

sonu