Never mind
There are two files to replace, not one.
anim.idx
anim.mul
Just did not see the other file in my mess of files in the folder I was working with.
So it did take the changes I made.
Deciding if I want to dive into this or not.
But if I do, I would want to be able to add new things into the game.
Probably starting off with some animals or monsters if possible.
So that is where I started.
Followed a video
got
visual basics
https://github.com/ServUO/ServUO
and the latest...