I get tired quickly when I try to exercise. How do I get myself started working out?

Gradually. It's best to start short and easy and gradually make your sessions longer and more intense, even if you have to start with only walking 5 minutes at a time. Can you do that 2 or 3 times a day? Try working up to 30 minutes a day by a minute or two every couple days. When you get there, try going the same distance at a faster pace. If you go too fast too soon you may get discouraged and quit.