The idea behind a track system is that it will allow your horse to live in a way that is much more in keeping with how they would live naturally if they were in their herd in the wild. Horses are designed to forage. On average, horses will walk 35 miles in a day, just wandering mainly - searching for food from grass and hedgerows as their digestive systems are designed for regular small amounts of forage.
There is an awesome Facebook group - Horse Track System - that I have joined and is proving hugely resourceful for working on and planning our track. I highly recommend joining this group to learn more.