I have created a calendar in LaTeX using MiKTeX and although the whole code is correct I have 12 warnings about underfull hboxes and overfull. Can someone tell me first how to make my code run without warnings, what is the result of these warnings and what these warnings specifically mean?
Overfull boxes mean that some text is wider than its specified box (either it's a one line box with too much stuff in it, or a multi-line parbox, but TeX could not linebreak at an acceptable place)
Underfull boxes mean that there are boxes with not enough content or stretchable white space glue to fill its specified width. Either a one line box with not enough stuff in it or a multi-line parbox but TeX could not linebreak at an acceptable place.
You can turn off warnings as detailed here
But usually you shouldn't and it is better to fix the text.