Your goal, especially at first, is to keep your activity simple. Slowly work up to 30 minutes of activity a day. But you don't need to do it all at once. Break it up into smaller chunks of time. For instance, you can be active in 3, 10-minute sessions a day. You can also combine being active with the other things you need to do. For instance, stand up from your desk and walk around often when at work. Or go for a walk around the mall before you shop.