A:
It would depend on the type of cell phone you have. for instance with an iPhone you can transfer your music via iTunes.
With an Android you just drag and drop your files from your cell phone to your sandisk the same way you transfer files from one folder to another on your PC.
Insert your sandisk into the proper slot on your PC, then connect your cell phone to your PC via USB cord. Locate the sandisk drive on your PC and open the folder. Now locate the folder that contains the files on your cell phone. Select which files you want to transfer, then just drag and drop your files from your cell phone drive to your sandisk.
Or you could google it, or check with your cell phone manufacturer for directions.