iTunes Help!

OK I have previously posted and asked for advice on this, and I seem to have got myself and my itunes in a mess!

So, I had itunes database files running from my MBP hard drive with the media files stored on an external drive, all has been fine for years...until I decided to make a recent back up of my media, including the database files from my MBP....

I copied both to a second external drive, and they work fine. So all good there, although my music folder has ended up being outside the itunes directory as I didn't agree to check the rename and move option as I consolidated ( don't know why I missed this!!), so my first question is - am I right in thinking a simple consolidate function with the music folder destination re-directed into the itunes media folder on this external drive will rectify this?

Sorry if I'm missing any obvious solutions, but as I have managed to screw up the database on my MBP and the original media folder on my original external drive, I'm now nervous about my next step and don't want to mess up the library on my second external drive!

And if that does rectify the problem and copies media files into the itunes media folder within the itunes directory....can someone give me the definitive step by step way of then copying the entire itunes library to another external hard drive? Would I be correct in assuming that once my music files are part of the complete itunes directory that it would then be a relatively simple task to copy them over to my other external hard drive? As I have tried a couple of times but I think that because the music folder with all my media in it is outside the itunes directory that this has failed.

As a result I have erased everything from my original external hard drive in readiness for a fresh and hopefully fully functioning copy from my second external drive. So if I have a fully functioning and tidy itunes directory which is the failsafe way of copying it to my empty external drive? As there seems to be fairly conflicting advice regarding theis, which is how I ended up with this problem originally!! ( step by step would be great as I have lost my confidence now..)

Also I think I may have mistakenly tinkered with the original database on my MBP too, so shall I completely erase this or not?...

I have a media library of over 300GB and really need it on my bus powered external drive rather than the mains powered external that it is currently on, but my main fear at the moment is creating any problems with my remaining functioning library on my mains powered external...and the nagging fear that my head may melt down before I can resolve this!!

I'll do a bespoke dj mix for anyone offering me a clear solution in way of thanks!