By default, the top row of keys on a MacBook performs the actions printed on the icons (Brightness, Volume, etc.). To use the traditional "F-keys" (F1, F2, F5), you have to hold the Fn key (or the Globe key 🌐 on newer keyboards).
If your shortcuts are acting weird:
The short answer: But that doesn’t mean you can’t refresh — you just need to know the correct shortcuts and contexts. macbook refresh key