New to my fitness pal

More about me. 36 years old. BMI of 40 and my cardiologist said I need to weigh what I did 20 years ago which would be 90 pounds to help my heart failure. Current weight is: 212 pounds. I joined weight watchers and lost 6 pounds in one week. Sure most of that is water weight as I quite drinking cokes and started drinking water. Looking into getting into the gym vs a home treadmill. Have 2 kids and just started a new job working full-time as a critical care nurse in a heart unit. So seeing my patients every day with complications from heart problems and high blood pressure makes me want to change my lifestyle for the better.