Replace Songs and Library on iPhone

After a crash on an old PC desktop, I lost most of my music files. I was able to rebuild the iTunes library on a new PC desktop from backup music files. It's now stored on a separate external drive.

The problem is my iPhone still has the old iTunes library and older files on it. I need to replace all that with the new files and library.

Is this process as simple as removing all music files from my iPhone and removing the Music app from the phone?

Thanks.