I don't know if anyone has done this as well, but I have been doing this for over 15 years. the tyres not only contain the soil or "growing medium" therefore avoiding the need to "earth up" but the rubber in the tyres traps the warmth of the sun and retains it for a long time. first obtain your tyres, obvious isn't it?, you need 3 tyres for each "tower" you are going to build. I generally lay down a covering of cardboard on the ground first, this is for weed suppression purposes, of course you could buy some weed control fabric instead but I tend to use what I can obtain. you don't really need this for just one tower as you can easily weed around one tower but if more than one tower is required sometimes weeds get in between and this makes weeding easier. so lay your cardboard flat on the ground where you are going to grow your spuds, if you can get cardboard sheets-great! but I generally get cardboard boxes and cut them flat. put your first tyre on the ground and arrange your ("chitted") spuds with space around them, no more than say 4 spuds will be required, you don't need to buy expensive "seed" potatoes, any potato will do, cover the potato with soil or whatever else you intend to use, I use cheap growbags-slit them open and pour the contents over the spuds, to the level of the top of the first tyre. in a while the potato plant will start growing, when its shoots come through the soil level place another tyre on top of the stack and fill with your "growing medium" or soil, when it grows through this, place another tyre on top and repeat the process, 3 tyres are usually high enough. if you build more than one tower, don't put them too close together or the tyres wont stack properly. don't forget to water and good luck.