This means that by
taking just one day holiday, you have at least 3 days off, and usually
rather 4. Let's take an example :
If
you take Friday off, this means that you will enjoy a 4 days weekend,
from Thursday to Sunday. In French you will hear "faire le pont".
You may also say : je fais le pont. If you translate literally
- je fais : I make
- le pont : the bridge
In French, litterally, you'd translate this expression saying : I make the bridge!
Welcome to France, enjoy the French language!