About the C#aug chord
To play C# 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
C#
Quality
Augmented
Notes
C# · E# · G##
How the C#aug chord works
C#
Root(1)
The home note. It gives the chord its name.
E#
Major third(3)
The major-third interval that establishes the chord's major base.
G##
Augmented fifth(♯5)
A raised fifth that expands the triad.