Honestly, you won’t. But until your kid is in full time school a 20-30 minute workout even everyday is eminently doable. Run around the local park, pull ups on a bar in the door way, press-ups, lots of exercises you can do to stave off muscular and skeletal atrophy which is what most of us at desk jobs literally suffer from due to chronic inactivity.

I would definitely recommend going for calisthenic training with an emphasis on isometrics around young kids, rather than weights(equipment and prep time) or intensive cardio(too much time-on-task). Holding a bridge, squat-and-reach, or a downward dog for 30 seconds while the kid crawls around is feasible, and a few rounds of that daily will do a huge amount of good.

You really don't need a gym. Get a pull up bar and some gymnast rings and just do what you can when the child naps. Even better add a bike trainer for cardio since you can't leave the house to run anymore either.

Caring for a toddler means being shackled to a creature that is entirely dependant on you, but there are still ways you can work in some self care while taking care of them.