Peel and cut your potatoes into 1" cubes. It doesn't have to be perfect, just about that size.

Put them in a large pot, and fill it with enough water to cover the potatoes.

Add about 3 Tablespoons of salt to the potatoes.

Bring the pot to a boil and let it continue to boil until your potatoes are soft (about ten minutes in my experience.)

Strain the potatoes.

Dump the potatoes into a large mixing bowl.

Add in the butter and milk and salt to taste.

Use an electric mixer and beat the potatoes until you've removed most of the lumps.

If your potatoes aren't creamy enough, add in another splash of milk, or another dollop of butter. It's best to taste them and see if you think they need more milk to tone down the salt, or more butter to give them more flavor. Add just a small amount of either one, because once they're too runny there's no going back.

Serve immediately.