When I started I did a lot of research into body types and amout of calory intake necessary to be healthy and how quickly exercise showed results.
Then I decided what kind of working out I wanted to do. Circuit training, yoga, power yoga, dance based, body weight training, etc.
I chose body weight training because it matched my temperament and then I looked up youtube channels and apps.
Now I follow my youtube channel religiously and do those workouts.
Mind, you won't always feel like working out and sometimes you won't, and sometimes you won't be able to but as long as you keep coming back and continue to exercise you'll reach your goal.
Tldr version- reaserch some, make a choice and start with whatever you have. It will build from there. Oh and don't stop, take breaks but don't stop.