Notes on E and A

The natural notes (the white keys on a piano) run A B C D E F G and start again. Between most of them is a fret's gap; between B–C and E–F there's none, just like the piano has no black key there.

Learn them on the two lowest strings first. Every barre chord and scale later on is found by its lowest note on the E or A string, so this pays off for years.