Walking is always a good part of any exercise plan. If you're new to exercise, start out slowly, by taking a couple of 15 minute walks daily, then increase as you gain stamina.
You could try, also, adding in 30 minutes of yoga 3 day/week. You also need some strength training, which can be done with light hand weights and moves, such as squats and lunges. You could alternate yoga and the strength training and take a walk daily.
There are many other forms of exercise that are also very good, such as swimming, biking, dancing, etc. You have to do what you enjoy and will be able to stick with and can include in your schedule.
Cardio/and resistance is key
You can try 3 days of cardio like walking, running, eliptical etc.. on Mon-Wed-Fri
Strength training on Tue-Thurs lunges, lifting weights, squats, planks, push-ups etc..
Yoga once a week to relieve stress.