How do I move my music, pictures and apps et cetera from my phone's memory over to an SD card which I had to buy? I fitted the SD card into the phone (Nokia Lumia 520 - running Windows Phone 8) only to be repeatedly told thereon that I still need space and I should move some stuff over to the SD card but I'm at a loss as to how that's done. Can you help please?
You should be able to transfer data to your new SD card using the Storage Sense app - you'll also see that there is the option to save new items (photos/videos/etc.) to the SD card, as well as the option to install new apps to the SD card.
Not all apps allow themselves to be installed on an SD card, and some may need to be moved back if the developer enforces that for an app as part of an update.
Go to the Microsoft store and download the Files app. This is a file manager application. Use that to browse through, and manage the files on both your phone, and your Micro SD card.
Try moving them manually using e.g. either the Files app or (Windows 10 built-in) File Explorer app.