Then I suggest you buy a yoga mat. I've seen too many people buy this fitness stool! More than 80% will end up in the corner and cannot be sold.
Push-ups exercise the shoulders, chest and back of arms, and also exercise the abdominal muscles to some extent.
Pull-ups, mainly exercise the muscles of the hands, forearms, front and back of the arms, and to some extent exercise the abdominal muscles and the back of the shoulders.
Squat, can exercise to the hips, thighs, calves and lower back. If you master the correct breathing method, you can also exercise your abdominal muscles to a certain extent.
There are many kinds of movements that specialize in abdominal muscles, such as flat support, belly roll (semi-sit-ups), knee hanging, knee sitting, supine leg lifting, crocodile crawling and so on.
You might as well buy some heavy dumbbells or kettle bells and barbell pieces for this stool, or you can do intensive training as a load in the future.