Create Animation Clip with sprite sheet

Hello,

I try to create many animation clip in a script, because I have many sprite sheet.
Every sheets are the same:
1st line: idle left
2nd line: idle right
...

My aim: select a file, and make some animation clip to assign in an animator override controler
I searched, but I don't know at all how to do it.

I saw that:
https://answers.unity.com/questions/1080430/create-animation-clip-from-sprites-programmaticall.html
But i don't know how to use it.

So, please, how to do ?

Sorry, english is not my first language.