This lesson is just a brief explaination of how to learn the notes on the guitar.
Take a look at a piano keyboard. Notice how there is no black key between the notes E-F and also B-C.
Look at the low or high "E" string on your guitar. The notes E-F and B-C will always be next door to each other with no fret in between! Start with another string- say... the "G" string for instance, going up the open string from G, skip a fret and it's A, skip one to B, then C is right next to it, now skip one more to D, skip to E, then F is right next to it, then skip one again and you should be at the Octave (double dots) on "G".
Do the same for all the strings on your guitar- check if you've got it right by what note your on at the 12th fret (octave, must be the same note name as the open string you started on).