Scan for media

Basically I need help!! once I had connected up my iphone to my computer and I had gone onto itunes it was asking me to either scan for media or go to itunes store. These were the only two options I had. I had previously scannedfor media several times in which it did nothing but show me the same screen each time. How do I get round this and just get onto my itunes library to sort my music out.

Would be grateful for help 🙂