The best way to test what you have done is to pick one of the projects (perhaps a fairly simple one to start with) and give it a try.

Here are some of the tutorials I would recommend as a first project:

• http://learn.adafruit.com/raspberry-pi-e-mail-notifier-using-leds
• http://learn.adafruit.com/playing-sounds-and-using-buttons-with-raspberry-pi
• http://learn.adafruit.com/matrix-7-segment-led-backpack-with-the-raspberry-pi
• https://learn.adafruit.com/adafruits-raspberry-pi-lesson-12-sensing-movement/overview
• https://learn.adafruit.com/adafruits-raspberry-pi-lesson-13-power-control/hardware