WHO suggests at least 150 minutes of moderate activity a week for adults, plus strength work twice a week.
Starter plan
Squats, wall or knee push-ups, glute bridges, planks and marching in place. 10-20 minutes, 3 days a week, then build slowly. Use the Workout planner on this site.
This is general information, not a substitute for medical advice. If you have a medical condition, are pregnant, or take regular medication, talk to your doctor first.