Strength Training Program Question

Hi there! I am currently in my 3rd week of the Couch to Sprint training program and am not sure if I am reading the strength training part right. It says to do Leg exercises AND Core #1-2x. I have read that as doing Core #1 and Core #2, I have been doing 1 - 2 sets of each core exercise in addition to the leg exercises twice a week as is listed in the training program. Am I reading that right? I got a little confused reading the definitions for the strength exercises. Not sure if I'm really supposed to do a different set of core exercises each time or if I'll switch as time goes on. My race is not until August so I am planning on starting with this program and then moving on to another one, such as the Beginner Sprint (I'd appreciate suggestions there as well). Thanks so much!

Jamie