You will encounter the following icons so you might like to familiarize yourself with them first:
These icons play a sound file corresponding to the lesson.
These icons play a sound file corresponding to the lesson without any other instruments and often at a slower speed so you can hear the guitar part more clearly.
These icons are for practising with a backing track.
These icons play video footage.
These green CD jamming spot icons are similar to backing tracks except the emphasis is on creativity rather than practice. They are an opportunity for you to play along without being told what to play.
These red CD icons follow some jamming spots with the inclusion of my own suggestion. Try not to go to this until you have spent plenty of time creating your own part.
The book icon help you consolidate musical theory concepts by asking you a question.