Are you looking to move just the music to the SD card or all apps and everything like that moved?
Make sure you insert your SD card into the tab, and it may tell you it needs to be formatted. If it says that, let it format it.
Go into File Manager, and select the files you want to move. Find a button that has like three dots, "More" or maybe even a button that says "Move". You can also do copy and paste. Once you choose move or copy it will show you a location. Navigate to the SD card and then click the "Move" or "Paste" or "Done" button. The buttons change depending on which tablet you are using so it makes it a little tricky. Your files will now be on your SD card.
This should work for you, you can also move your apps there as well, and other files if you wish.