You could start with a 30 min walk everyday... try parking further away from places so you have to walk further.

Don't be so hard on yourself, if you treat it as a chore you wont enjoy yourself. Or maybe you could get a walking buddy and that way you can chat while you walk and you dont realise how far you have walked or how long its been.

Ive found if i have someone doing it with me i stick to it!

Good luck! and good work on losing the baby weight