Hi,
Connect the phone to a PC using the appropriate USB cable. If the phone is already switched on there will be a notification to select the appropriate USB connection on the phone. Select the option that allows file transfer.
Once this is done the PC will recognize the phone and connect to it.
You should now be able to use Windows Explorer to find the phone's drive(s). Locate the ''Music'' folder. Copy and paste the music files from your pc to the ''Music'' folder in the phone.
When finished, unmount the phone from the PC (taskbar icon) and then disconnect the cable from the PC USB port and the phone. Switch off the USB connection in the phone.
Open the Music app in the phone to find the music file you want.