Justin Sandercoe teaches us how to play power chords with a 5th string root note in this tutorial. Start out by placing your first finger on the root note and your third and fourth finger underneath. The tip of your fourth finger should be touching the sixth string. Push the tip of it up until you've trained it to always touch the sixth string, without this the song will sound terrible. Once you have the chord shape down, you will need to start to play some riffs. Move the fifth string root around by going from D to C to F to B flat. Continue with this, then you will have the process down!