Start with a light load, gradually increasing the duration and pace. You should raise the length of your walks first, and only then increase the tempo. The loads should be adequate for your health.
Practice walking regularly. One walk a week won't do you any good. If you can't take walks every day, then do it at least 2-3 times a week. It can be done at any convenient time but no earlier than 1-1.5 hours after a meal.
