Usually phone manufacturers provide software to accomplish that, but i know from personal experience that these softwares can be buggy. If you don't have that software or it doesn't work properly, configure your telephone as a storage device and transfer your music that way.
Once you configure your phone as a storage device and hook it up to your pc, you'll see a new drive letter in your "my computer" with the mention "storage device". drag and drop your music to the storage device and it will load into your phone.