How to make simple autofire work in Mame 2.2.6

I am using Mame to play Final Fight.

I always want simple auto fire for punch button.

How to do it?

1st I have to turn on autofire plugin right?

Then I open final fight rom and go to plugin

I saw this

Okay I am very confused here.

First I want to get rid the existing autofire buttons and start over. How do I do so? Where is the setting saved?

Then how does it work? I want punch button to be autofire.

Should I use some front end? Can I do this with Vanilla Mame?

How does it work anyway? We press the autofire button and then we press the correct button?

Can I have a button for normal and autofire to be different buttons?