Connect the phone to your computer with a USB Cable. If the default connection mode is not set to Media sync (MTP), open the Notifications panel and tap USB connected > Media sync (MTP). Your computer will prompt you with different actions to take. Choose to open the folder to view files.
Use the computer to organize your audio files then create a music folder. You can use subfolders to organize your music files, or you can simply copy the audio files into your phone’s memory.
Use the computer to copy music and other audio files into the music folder (or subfolders) that you created.
To disconnect your phone, open the Notifications panel and tap USB connected > Charge only. Then disconnect the USB Cable from the phone.