How to Transfer Music from PC to My Old Galaxy Mini?

Yeah, the options can be pretty sparse on older phones like this one. If you connect the USB cable and nothing happens, just swipe down from the top of the screen when you see the charging notification. Tapping that should give you the option to switch to file transfer.

When you plug in your Galaxy Mini, there should be a notification that lets you choose how you want to connect it. Make sure you select 'File Transfer' instead of just charging. If that doesn't pop up on its own, check the phone's settings for a similar option. Sometimes it's a little hidden on older devices!