How to customize page or post view of admin UI.

[kouohhashi]

Hi,
I'm newbie here.

I want to add a button on right side of admin page like below.

And when a user click it, I want to do some background processing and modify database.
Could you give me some instructions or resources I can dig into.

I could not find solutions probably because I'm not good at TypeScripts.

Thanks in advance.