Watch the Alternate Picked Pedal Trip online guitar lesson by Jennifer Batten from Rock Sauce For Lead Guitar
It's important to have your alternate picking skills in order for this technique. If you have trouble, practice just alternate picking different four finger combinations on one string and get comfortable with it before jumping strings. Choose any fret to start with and play 1, 2, 3, 4 or 1, 4, 2, 3 etc. Then pick each note twice, then 3 times, then four times.