Simple plan is best, as serotoninsid says.
Increase longest run each week (5miles now) by 10% per week.
Days off ( 1, 2 or 3) if as you feel the need to recover.
Get suitable running shoes, and clothing.
Try and keep on grass or tarmacadum surfaces.
You will be up to 10 miles with ease in due course.
Run based on time only, not about pace.
Forget about heart rate monitors, distance measurement and other gadgets.
The batteries on the heart monitor ran out and I stopped using it, it's a pity as it is an expensive enough piece of kit.
Forget about heart rate monitors, distance measurement and other gadgets.