What do you do to lose post baby belly pooch?

Jw, this is my first child, and normally my metabolism is rediculouy high, so much to the point that I never needed to exercise to stay trim. Now though, at 12 weeks PP, I am still 10 lbs above where I want to be, and it's all belly. Since exercise wasn't ever really a thing I worried about previously, I don't know what exercises would be best to trim belly fat. Anyone have any hints/tips?