By doing is always the answer. Make small steps. 3 months ago I used to be the kind of person who studied 0 min every day. So, I decided I'll make a small goal to study atleast 5 min a day. I know 5 min feels like nothing, but I made this limit just to make sure I studied. I can study for 5 min if I haven't already before going to sleep. So by making a goal so easy to achieve, all I had to do is follow it. And on most days I studied 1-2 hours. Yes, I skipped some days, but after 3 months I'm in a situation where I can atleast think about passing the exams I'm giving, and this habit is coming naturally to me. I wanna study now, and I don't have to force myself.
So you see what I'm getting into?
Make a small goal for yourself. If losing weight is your top priority then you may make a small goal of running 2 min a day. It will feel nothing, but it'll help you get started and when you'll be in the zone, you'll just say yo yourself: What? No, I can do more than this for myself.