ITunes isn't allowing me to add music to my iPhone?

I plugged in my iPhone and it's up to it's current software and so is my iTunes, I don't have a folder playlist so when I went you go create one the playlist button it doesn't allow me to click it? I tried dragging and copying music over but it doesn't add. I have no music or videos on it, how do can I add music to my iPhone, thank you.

That's why I buy my music.

Have you any music in your iTunes library? Will it play on the computer from iTunes account?
If you have not legally added music to iTunes account, it will not sync to a device and will appear gray or with a! Next to the song.

To add music to the device: click on the device button at the top right of screen. This now shows your iPhone Summary screen.
Click on music tab. Click on sync music.
Select songs, playlists (if you made any), genres, etc.
Select apply from bottom right
Wait, then select sync.