Very very easy.
Boil three potatoes per person. Idahoes are very nice.
Peel potatoes. Chop in half. Boil for about an hour or until the tip of a knife goes clear through the potato without any resistance. Drain potatoes in a large collander. Return the potatoes to the pot (now emptied of water but still on a low flame....this will help to evaporate whatever moisture is left...you want the potatoes to be dry before you start to mash them). I find a metal masher is best. Once you have started to break them down add a splash of whole milk, a dash of salt, and a chunk of butter.....adjust the milk, salt, and butter according to the number of potatoes in the pot. Mash quickly, turn the flame off, and cover the potatoes until ready to serve.