How do you start an exercise routine?
 

1.Start slowly. Gradually build up to at least 30 minutes of activity on most or all days of the week (or whatever your doctor recommends).
2.Exercise at the same time of day so it becomes a regular part of your lifestyle. ...
3.Find a convenient time and place to do activities.

Start out slowly and progressively increase:
Give yourself plenty of time to stretch or take a leisurely stroll to warm up and cool down. Then pick up the pace until you can maintain it for five to ten minutes without becoming too exhausted. Increase your workout time progressively as your endurance gets better.

Exercise is not a competition. Start slowly and build up gradually. For example, choose something you like, for me, it's pilates https://betterme.world/articles/wall-pilates/. Then speed up to a pace you can continue for five to 10 minutes without getting overly tired. As your stamina improves, gradually increase the amount of time you exercise. Work your way up to 30 to 60 minutes of exercise most days of the week.