Whenever I set the background color to red, there should be a buzzer, but I cant seem to figure out how. I also want this to be global as there will be multiple pages with the background color of red
Hi
How many pages is Multiple Pages (actually Screens, not Pages)? To apply globally at the same, you would be best to use Virtual Screens.
When we define virtual screens, we use one 'real' App Inventor Screen (most often Screen1). Screen-sized Vertical Arrangements on it are displayed/hidden as required - they are the Virtual Screens. This is generally a better approach for multi-screen Apps, they share data without having to "pass" it between screens and it also reduces code duplication, making the App more efficient and the code easier to follow if you have to return to it at a later date.
So, instead of seperate houses, virtual screens are rooms of the same house.
Edit: Previously uploaded blocks were wrong! 
.... and a Virtual Screens example by TimAI2:
https://groups.google.com/g/mitappinventortest/c/K-zAr2X3nio/m/qzrDox_pBgAJ?pli=1