No reason to jump straight into manual mode. Use Av (aperture priority) and Tv (shutter speed priority) modes (and pay attention to the camera settings) until you get a good idea of how to control your depth-of-field, capture motion effectively...and how both of those affect the image exposure. (don't forget about playing around with the ISO setting)

Only once you have a good familiarity with those modes would I spin that dial to full manual mode.

If the light is good, I usually leave it in Av mode because I am usually more concerned with image sharpness and depth of field (slow moving or non-moving subjects).

Good luck.