Q: Using new computer to find iTunes media folder on external hard drive

Please help! I've wasted most of the day on this so far!

I have followed the steps suggested on how to move my music from one laptop to another. The old laptop only read from an external hard drive anyway, which is what I want my new one to do also. The music files and iTunes media folder are therefore already on the external hard drive in readiness. I followed the next instruction (open iTunes on my new laptop and hold down the shift key) and showed the computer where to find the external hard drive, which it could. However when I opened the "iTunes music folder" (which is where all the music is stored) I expected to be able to click OK. However it seemed to be waiting for another file (an iTunes library file?) but that's as far as I wanted it to go. How do I resolve this please? I know it MUST be a simple problem, but I just don't understand where the steps have gone wrong as I've followed them to the letter (or so I thought). Please help me resolve this once and for all.

Thanks