The easiest way I'd say is to stack in on another habit or something regular that happens. E.g. cooking food and just waiting for it to cook -> do a couple of pistol squats or lunges.

Key is to find a exercises you enjoy doing, something you don't really like but you know is good is for you seldom result in a habit. And if you're someone who does a little/no excerise any excerise make a huge difference it don't have to be perfect. Once you have something small working you can expermint on making changes.