What can I do to work out after giving birth to lose that weight?

Take it easy. If you are breastfeeding, do not overdo it with exercise and diet immediately postpartum; you can wear yourself out and dehydrate, causing your milk production to drop or stop. I would recommend more consistent and deliberate lifestyle changes, e.g. Daily 30-45 minute mild-moderate exercise, avoiding carbohydrates such as sugar and pasta/bread and getting at least 8 hours of sleep daily.