DC motors for a 2 wheeled robot
That's still a little vague. Have you purchased any parts yet? If you haven't purchased any parts you may want to consider doing the $50 robot tutorial on this website. It's a simple 2 wheel robot.
If you have purchased some parts let us know what they are and we can help more specifically. When connecting a motor to a wheel you will probably want need some type of hub. A hub connects to the wheel and the shaft of the motor you are using. When you purchase your motor it should have information about what the shaft size is and if it's round or if it is shaped like a D.
You may want to look at "Gear motors" they are motors with external gearing that makes them spin slower but with more torque. You would connect to them the same way as a standard motor.
Good luck with your first bot. Make sure you post pictures.