Working out? When and how

Kat • Im a lucky momma of a beautiful 3 year old girl. Hubby and i conceived baby number two after one cycle of trying! super greatful to be due Jan. 18th 2017
So I had my baby on Christmas and just had her 2 week check up. The midwife gave me the OK to start a workout. When did you ladies start a fitness regimen and how intense did you do