iRunes: Moving iTunes Files (Self Managed)

I'm trying to move all my music to another drive and I don't let iTunes organize my music for me. I moved the "iTunes" folder to my external and I also moved my Music folder which is also outside of my external but the issue I'm having is when I export the XML file.

In Itunes I went to File > Library > Export Library which exports an XML file.

In the XML file I see a ton of paths that begin with:

file:///Volumes/Data/Music/

So my plan is to change all the files from beginning with that to:

file:///External/Music/

That way iTunes can find my files. I haven't done the last step yet because when I option+click the itunes file and it opens up to the message with an option to "Choose Library..." when I click this option it won't let me select the XML file I just exported but an ITL file in the

iTunes/Previous iTunes Libraries/

folder where there are some files with the extension ITL and some that dont have an extension at all.

How do I move my files from my self managed Music folder on my hard drive to a Music folder on my external?