An excellent start, theres nothing wrong with using Auto, it's there for a a reason. As you take more pictures you will then understand what the settings are being used by the camera and if you like the results they can be a starting point when you feel ready to try aperture, shutter or manual modes.
With the boy photo, have a good look around the background and see if there are objects which would be better not in the picture, as in this case, the headroom barrier to the left. It's little things like these which can help a photo, the composition.