About the Aaug chord
To play A augmented, use the first shape above. Place your index finger on the 1st fret of the C string, your middle finger on the 1st fret of the E string, and your ring finger on the 2nd fret of the G string. Leave the A string open. Strum all four strings and check that each one rings cleanly.
Root
A
Quality
Augmented
Notes
A · C# · E#
How the Aaug chord works
A
Root(1)
The home note. It gives the chord its name.
C#
Major third(3)
The major-third interval that establishes the chord's major base.
E#
Augmented fifth(♯5)
A raised fifth that expands the triad.