Some experts recommend walking to be the best exercise you could do, it's very easy and effective and you're less likely to get injuries from doing it than you would with other exercises. What you need is consistency and a schedule, set yourself a time to do this activity and stick to it. Try to do it three times a week for 30 minutes and that's enough for the average person. After you get better then you can start doing other routines trying out new things. If you only kept walking there would be nothing wrong about it since walking is perfectly fine and enough for most people.