Hey Chuck,
You can strum all the way through it if you want to, whatever works best for you. I didn't know you were a newbie, or I would have responded a little differently.

You don't have to do the riff all the way through, but you may think of it as a goal. Here's something to practice, when you switch fingers for the chords. Hammer on when you put your fingers down, all except for the last one when you go back to the C.

I'm glad I could help you, and let me know if you need anything else.