As simple as it sounds, you start by figuring out the WHY. Why do you want to get fit? 

Do you want to get fit to be healthy?

Or to be physically stronger?

To gain muscle?

To fit into old outfits?

To have more energy?

To set a good example for your loved ones?

Once you figure out the “why,” you can then figure out the right fitness path to take. Your reason for wanting to be fit is what will pave the way to keeping you focused and motivated.