About the C#sus4 chord
To play C# suspended 4th, use the first shape above. Use your index finger to barre the 1st fret across the G and C strings. Place your middle finger on the 2nd fret of the E string and your pinky finger on the 4th fret of the A string. Strum all four strings and check that each one rings cleanly.
Root
C#
Quality
Suspended 4th
Notes
C# · F# · G#
How the C#sus4 chord works
C#
Root(1)
The home note. It gives the chord its name.
F#
Perfect fourth(4)
A suspended fourth that replaces the third.
G#
Perfect fifth(5)
Adds strength and stability.