While the milk is getting warm, pour the polenta into the milk and stir.
Add the butter, salt, and black pepper as well.
Keep on stirring, in fact never stop stirring.
The heat should be on medium, not slow but not overly hot either or it can burn.
While you are stirring, the polenta will get thicker which is all good.
Once the polenta starts to bubble, take it from the heat. Even if it still looks liquid because it will suck in the remaining milk and will quickly harden if you overcook it.
Serve the creamy polenta hot as a side dish with other meals.
Video
Notes
See in my post for different flavor variations and ideas to pep up your polenta.