Q: How to move my iTunes library from an external hard back to my computer hard drive?

I have my iTunes library and folder on an external hard drive and everything works fine. There is no iTunes folder on my computer hard drive. I've the tried the instructions on these two Apple support pages and they don't work:

iTunes for Mac: Moving your iTunes Media folder - Apple Support

How to move your iTunes library to a new computer - Apple Support

First method above: I tried opening iTunes, go to preferences, change location of library, create new iTunes folder, go to file and library and "consolidate files"; all the files copy to my hard drive. However, the iTunes library files are still on the hard drive, so when the hard drive is disconnected, iTunes can't find any files.

Second method: Copy the entire iTunes folder from hard drive to computer hard drive. Open itunes, and select new folder location in advanced preferences, organize files when prompted, then consolidate files; at this point, every single file has an exclamation mark by it because the computer can't locate the file, and since I have several thousand files, this is a big deal; I can't just find each file individually for the program, as it would take the rest of my life. Hlep!! or rather, please help!