Can't sync music from iTunes to my iPhone 5S

I have an iPhone 5S on iOS 8.3, managed using iTunes 11.4 on my 2006 MBP running 10.6.8.

Simply put, how do I get music onto it from iTunes? I synced music to it last summer when I first got it, but I can't remember what I did, and now I can't get it to work. I'm used to just dragging songs from the library over to the device in the sidebar, but that's not working. Am I supposed to create a playlist and sync that?

EDIT - I've just reset it to factory settings and restored a backup, and I still can't find a way to get any music from my iTunes library on my MBP onto the phone. My purchased music is showing up on the phone as being available to download from iCloud, but that's all.

I've tried going to individual tracks, clicking the right-pointing arrow and choosing "Add to>Device>iPhone", but iTunes just sits there for a while saying "Preparing to update" and then nothing happens. The track doesn't get synced to the phone and I get no message telling me of any kind of failure.

Is the problem that I'm still on iTunes 11.4? It's the most recent version that will still run on 10.6.8 AFAIK - and I can't update my OS any further because I only have a Core Duo CPU, not Core 2 Duo.

adamhenry said:

Dragging and dropping seems like a hard way to do things.

Click to expand...

Well, it's actually very easy. But my issue is, it doesn't work for my iPhone. It works fine for my iPods.

Should it work on my iPhone?

EDIT - I've just tried it using iTunes 12.1 on my iMac at work, and dragging and dropping works perfectly. I guess I'll just have to put it down to incompatibility between iTunes 11.4 (and/or Snow Leopard) and the iPhone 5S.

EDIT EDIT - this looks like it's my problem. I'll check it out at home later.

Just in case it helps somebody, the problem was indeed with iTunes 11.4. By deleting the .kext file specified in the link I give above, and then re-installing 11.4, I've now got my MBP playing nicely with my iPhone again.