Stuck at "Jazz piano Fundamentals"

I very recently bought the book "Jazz piano fundamentals vol 1" From Jeremy Siskind. The first excercises were pretty easy but I felt like it took a huge leap from the first to the second coordination excercise, (Playing "Charleston" rythm along with a swinged scale) I just can't quite grasp the swing along the rythm, separately I don't struggle at all, but when putting them all together it seems impossible. Someone has any tips to get the hang of the swing?