Watch the Mute Master online guitar lesson by TrueFire from Play Acoustic Guitar 4: Rhythm Principles
Mute Master - Playalong is a video guitar lesson presented by Brad Carlton and is sourced from Chord Studies: Open String Chords Vol. 1.
You'll find these open voicings a bit more challenging as you must make sure you mute the indicated muted strings, while leaving the indicated open strings open. The first E voicing and the A add9 voicing are played with your first and second fingers while the other E voicing and E maj9 are played with the first and third fingers. Mute that A string with whatever finger feels most comfortable for you.