How to move certain files to certain folders?

I am trying to speed up Re-Labeling all my metadata for every song in my library. Basically I need to create a workflow first, but I am having some troubles on how I should be doing it in Automater. I will explain what I need and hopefully someone could help me create a workflow to make it happen.

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Example filename: "forrestaveryderty_driftinonby_flapjack.m4a"

find all filenames that start with the same word before the First underscore (_)

create a folder with that same word

copy files with the same word (BEFORE THE FIRST UNDERSCORE) to their corresponding folder name

I then can use Media Rage to select the certain folder and and change the artist name all at once.

and I would like it to do that with every file at one time.

again...

1: Find files with the same name before the first "underscore"

2: Create a a folder for every different name found (before the first underscore)

3: Copy found files (with same name before the first underscore) to the folder with the same name