You have a good foundation, don't start from scratch, just go more,

Push-ups are in groups of 50 and 4.

50 sit-ups, 4 groups,

Get down in groups of 50, 4,

Leg lifts, 20-second groups, 4 groups,

Elbow touching knee (thigh lifting knee touching elbow) 20 (left side 20, right side 20), 4 groups.

Do the above five cycles, namely push-ups, sit-ups, squats, leg lifts, elbows touching knees, and then push-ups. .....

That's what I did. If you have time, take time out to run and play ball. Don't calm yourself down anyway. Don't sit for at least half an hour after eating, so you can see the effect in a month, but exercise to lose weight comes faster and you can see the original appearance as soon as you stop.