Set your metronome to 45-50 BPM and play the barre chords displayed below in succession (1st for 2 beats on the E string and then 2 beats on the A string).
If you don't like the displayed chords, you can always click the Refresh Chords button for alternates.
Use the timer to perform the exercise for a duration of your choice (2 minutes is recommended). Unlike some of the other exercises on this site, the timer is integral.