Hello and welcome,
Thanks for your query.
It is always best to start slow and take it up from there on, and once you reach a moderate level and notice a change in your energy levels, as well as a small amount of weight loss
, set this as your standard.
You can start with a 30 minute walk for the first day, at a normal speed (approximately 3-4 mph). Start increasing that by 5-10 minutes for the first week, till you reach the 1 hour duration.
Take at least a one day break per week. This helps in rejuvenation
of the body and is vital. For the next week you could try increasing the speed a tad bit (4-5 mph). Continue with the same speed for 2-3 days, and then again increase (5 mph).
Please do not increase the speed too much just because you think you can, but instead work up the ladder, which will help in increasing your metabolism
Once you reach a comfortable speed stick to it (around 5 mph). It should feel like you are brisk walking, and should be between a jog and a walk.
Brisk walking is really healthy.
Now to go about a a standard on a daily basis, with the one day per week exception. Start with a slow speed (this would be your warm up) for a minute or two, and increase your speed every 5 minutes, to finally reach the speed that you normally brisk walk on, and continue the same for the rest of the exercise.
Walking/hour = ~300-500 calories
I hope I have succeeded in answering your questions, you could write back to us anytime for further clarifications.