The ASuS4 Chord is found by locating the 1, 4 and 5 (A, D and E) of the A Major Scale: A B C# D E F# G# A.
So the notes of the ASuS 4 Chord are: A D E.
The chord chart diagram and video below will further demonstrate how to play this beginner chord.
Here is a key that will help you read the chart:
Chord Playing Tip: Be sure that you are pressing down on the string 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.