The first thing to point out about this riff is that the first two beats of each bar are very similar to what we saw in Exercise 1. So be sure to keep that part the same.
The main things new in this riff are the quick legato runs that begin on the second half of beat two in each bar. Notice that from that point on, there are only two pickstrokes. So your fret-hand is going to be doing most of the work using hammer-ons, pull-offs, and slides. The most important thing here is to make sure that all the legato notes are equal in volume. Practice this part very slowly and only build speed if you're confident that you're being accurate and the note volume is consistent.
Lastly, watch out for the "hammer-on from nowhere" at the end of bars 6 and 8. You'll be hammering on the Low E string from nowhere on the 5th fret, so make sure that particular note is equal in volume with the other notes.
Have it down? Then it's time to practice with the backing track! See you on the next page.