I am working on a spreadsheet which I currently manually populate with
specific objects (colour-coded stars) depending on the respective date that
that event occurs on. I want to implement a system whereby if I populate the
date column, that excel will place the appropriate object in the appropriate
column.

I have two columns for the two different types of star. I have one column
for everyday from start of June through to the end of February. Does a method
exist to implement this?