Here is a demonstration of my core workout. i recommend you use this and my written instructions in conjunction

You start with 10 crunches while bringing your knees towards your chest,

10 of the same thing but touching your hands between your legs

10 of the same thing touching your hands in front of your legs

30 side rotations where you keep your feet off the ground, knees bent, making a fist and touching the ground. right then left is one

30 where you keep your back off of the ground, kind of sitting up, and paddle your feet up and down, legs alternating, legs straight. up then down is one

30 of a similar thing where you position one foot directly above the other then switch the position. switch then back where you started is one

30 crunches with one ankle placed on the other knee

then 30 switched

30 bicycles where your back in the sitting up position, only the legs involved in the movement. one pedal with each foot counts as one

then 30 reverse bicycles

then the first 60 reps again

then the plank hold for a minute 30 seconds