A macro 4 a button to change any highlighted cell

I am trying to create an Annual Leave form with buttons at the bottom for Annual Leave, Lieu Time etc. I would like to be able to highlight a day on the calendar and click one of the0 buttons at the bottom and for the highlighted cell to change colour with a different colour for each button, if that makes sense. I am only just starting to learn Excel, so this may be way out of my depth! Can anyone help?