Download "daily workouts" app it has a variety of workouts for any area you want to work on and it shows you have to do them
Plank,sit ups,crunch,rise and reach,side plank,One armed sit ups,bicycle crunch,reverse crunch,peguin crunch,Russian twists,wall sit ,leg raise,superman,fire hydrant in and out,push ups :)
Crunches, toe taps, press ups, plank, wall sit, flutter kicks, side lunge, there are lots! x