Samsung galaxy 4 sd card default settings

Solution
Sounds like you're all set up for it so the way to gain more internal data storage space would be to move the photos and music folders to the SdCard.
It can be done but it's easier if your Galaxy 4 hasn't been updated to run Android Lollipop. Go from Apps to Settings>More>About Device. While you're there, tap it seven times to give yourself Developer Options.

Once you see the message that says you're now a developer, go into About Device and see which flavour of Android you're runng.

Post that information back here and someone will help, even if it's only me.
 
No, that's fine and enough information. 4.4.2 is KitKat and it's possible to do it but it might involve rooting the device which gives you more permissions to mess with the system. If the device is under Warranty, that could be invalidated and if you're in contract with a Service Provider, it may also be in breach of some of the terms of that contract.

All that done, start with the easy way. Go back to Settings>More then Storage. Is the external SdCard showing uop and is it mounted? If is offers you "Unmount SdCard" it's already mounted.

Back in Settings>More>Applications Manager and scroll the top menu to the right until you list the All list. Choose any App and see if it offers you the chance to transfer it to the SdCard.

Finally, use your File Manager App to find a random file - say, music. Choose a track and tap and hold it. Can you move it to the SdCard?

Anything else will need rooting.