You dont need Keys to transfer music and movies to the phone.
1st. thing make sure you have the drivers installed on your pc for the phone (if you have kies installed then the drivers should be as well.
2nd. Go into the usb settings on your phone [Settings - Applications - USB Settings] and set it to "Ask on connection"
3rd. When you connect your phone to the pc, it should prompt you on the phone how you would like to connect. Here, I just select mass storage so it shows up as a drive on the computer.
4th. After it connects pull down your notification bar at the top and select the usb to mount it.
After doing all of this you should see the phone as an extra drive on your computer.
P.S. If you want to try out Kies then just select Samsung Kies on the phone after connecting it to the pc. IMO Kies is buggy, slow and crashes alot.
Oh almost forgot. If you go the mass storage route, when you are ready to disconnect your phone use "safely remove hardware" in windows, then on the phone select to unmount before disconnecting.