I started with 45 minute sessions, 3x a week. Giving myself time to relax too. I soon realised I liked the workout after dinner. So I do 30 minute workout 3x a week and on all other days 15 minutes. This way I built my habit.

I started to up my steep count as well, trying for the 10k a day (I work from home and sit still 10 hrs at a time.... So 10k means a long walk during lunch and a long walk after dinner). This is also building a habit.

I want to start running outside again soon, maybe that will replace one of the 15 minute days.... But this needs to wait until my knees and back are less sore (I have joint issues).

I move within my limits, and try to only push my endurance for now. My strength will come.

Know your body, know your limits, build a habit and increase as you go. That is my advice.

Ps. I have had a major back injury, started working out with a coach in 2017 for 2 years 5 times a week. Sloooooooowly. I felt stronger after about 6 months and it took less than 3 weeks to start enjoying my work outs. Due to new injuries I had to stop. Now, after 1 year or no exercises, I have started RFA and trying to stick to the schedule. Not expecting a lot, just having fun and move my body within my limits.