Exercise does not only happen in a gym. Walking to the bus stop, cycling to a shop, playing with children and doing housework all require energy. The World Health Organization calls all of these actions physical activity. This means people can move more without buying special clothes or joining an expensive club.
A useful plan is to add movement to routines that already exist. Take the stairs for one or two floors, stand up between study sessions, or walk while making a phone call. Regular activity supports the heart, muscles, sleep and mental well-being. The best first step is often the one that is easy enough to repeat tomorrow.