Just to clarify, When you connect your phone to your PC via a usb cable, the default action is to charge the phone. If you pull down the notifications bar at the top of the phone screen, you will see, among other things, either:
1. "USB charging. Tap here for more options." or
2. "Android System. Contents hidden"
Tap either one to go to a screen that will let you select what you want to do.
If neither one of those options show up, you might need to download the Samsung PC driver. But I think the phone will install that automatically.