The C Sus4 (also known as C Suspended 4, C Suspended 4th) chord is found in the C Major Scale: C D E F G A B C. It is made from the 1, 4 and 5 steps of this scale, or the notes C, F and G.
Suspended 4th chords have a unique and beautiful sound to them. The C Suspended 4th chord is essentially a C Major chord, but we are “Suspending” or replacing the 3rd with a 4th, in other words, we are replacing the “E” with an “F” in this particular case.
Here is a key that will help you read the chart:
Everything on the above chart should be self explanatory, except for the last three in the third column. They may need a bit of explaining. The O, or open symbol, simply means that you do not press down on any notes on that string. The X means you do not strum that particular string. The Barre symbol means you need to barre that particular fret. When you barre a fret you are pressing down on multiple strings at the same time with one finger.
Chord Playing Tip: Be sure that you are pressing down on the strings hard enough. You should play each string one at a time to make sure you have a nice clean sound. If any of the strings buzz or sound muted, then something is not right.