Can anyone tell me the series of 5? I have heard it mentioned so many times and I know it is ab work but not sure exactly the order or the exercises it is?

It is the ab series consisting of single leg stretch, double leg stretch, scissors, lower lift and criss-cross.

Super. Thanks

Bunny ~ Here is a tutorial with all five exercises. I hope this helps!

Sorry just seen your answer - thank you.Gia Calhoun

I cannot do a roll up. Can you recommend how to work at this so I can achieve it?

HyperMobileJan  I recommend practicing a half roll back with your knees bent and hands behind your thighs for support if needed. I would also practice rolling down to the mat from seated. Practicing the inverse of the exercise helps build strength. I hope this helps!