If you want to get fit but do not know where to start, 
1. Abs "Butterfly"
Lie on your back, bend your legs at your knees and take them to your sides (opening your legs). Keep your feet together and your hands behind your head. Without bending your back, lift your torso slightly and hold the position for a couple of seconds. Returns to the home position. Repeat the exercise 10 times.
2. Exercise for the Oblique Muscles of the Abdomen
Lie on your back, bend your legs on your knees, carry your hands behind your head. Lift your torso a bit and stretch forward by changing your arms: first with the left, then with the right. The head and neck should be kept in the same line, while the lower back should be firm on the floor. Repeat 15 times with both sides.
3. Bicycle
Lie down, raise your torso slightly, bring your hands behind your head, keep your back straight. Touch your left elbow with your right elbow and then do the same with the opposite side. Repeat this exercise 15 times on each side. Do 2 sets.
4.Legs at the sides
Lie down on your back, put your arms at your sides, raise your legs. Without taking the torso off the floor, lower your legs to the right and then to the left without folding. Do 2 sets of 15 repetitions on each side.
It is necessary to repeat each runita 4 times a week to obtain real results.
Recommendations:
Perform Warm-up before starting routines
Drink lots of water
Proper breathing
Good nutrition: it is important to consume fruits, proteins and fibers to strengthen muscles