First try to start slow and short. For example I’m starting with running again and I’ll do my runs now with pace somewhere between 7:10 and 7:40 - easy run. I’ll run for 20-30min. Next run would be same pace but longer 35-42min. Run after that you can go shorter again. Most important thing is to not go too hard, because you cannot keep it consistent. Point is to adapt your muscles and joints to that type of stress and build up slowly from there.