The first notes to learn are the notes E, F and G on the first string.
The open first string is an E note. This E note is written in the 4th space of the staff.
When playing single notes, a much smaller movement of the pick is used than when strumming. The movement still comes from the wrist but involves hitting only one string at a time. Use a downward pick motion to play each note. A downward pick is indicated as