You have all the essentials.

Heart, lungs and will.
Although you can walk a Bigfoot in whatever attire you choose it’s advisable to have at least a few basics.
Shoes. Good shoes are paramount. There are many specifically designed for walking as support and comfort are the main priority. Get a properly fitted pair at the start of your training program.
Layers, Weatherproofing & leg-wear. The ideal walking garb is several thin layers and a light rain/windcheater. Fabrics which ‘wick’ are ideal. Never wear denim, if it rains
and gets wet it will stay wet and weigh a ton. Loose, light walking trousers or shorts will be so much more comfortable.
Sticks. Poles are great on long distance walks, and take up to 40% of the weight off your knees, transferring it onto the upper body. They’re not a necessity but we recommend them.
Water & Food. You should be drinking water little and often, a sip or two every 15 minutes. The same goes for food, nibble an energy bar every hour to keep your fuel levels right.