how can i transfer downloaded music from the sd card to the internal storage The music I download gets stored into my SD card. How do I get it to store into my phone's internal storage?
You should be able to move files with the built in file manager.  On my Samsung S3 phone, it's called "My Files" and looks like a file folder.  The manager has options to copy from SD card to device memory.  If you don't have a default file manager, you can get one (eg. ES File Explorer) from the play store.