First, you can start to eat healthy. Remove all junk food, sugary food from your diet. While doing that, you also need to incorporate healthy lifestyle. Take a brisk walk in the evening, and try to achieve small goals along the way; for example 1 miles on Monday and on Friday you try to get 1 1/2 miles of brisk walk. Small achievement will let you stay strong on tracks.

Don't do anything extreme like straight away join bootcamp and extreme dieting. Don't! Start changing the lifestyle then you can start for something more serious.

Good luck!