THE WORKOUT
Inner thigh crunches
Table top
Forearm plank with ball in between thighs - tailbone tucks, knee taps
Crunches
1/2 roll back + twist
Swan
Ab series
Stretch

If you don't have a stability ball just yet, you can use a pillow or do all of this without the ball. It's still a great workout!
THE WORKOUT
Marches
Planks - shifts, leg lifts, shoulder taps
Ball below the taps of the shoulder blades - crunches, pulses, table leg crunches, add twist,
All fours...