can't find valid git repository. Should I init git manually?

[5y1ee]

I start Obsidian today, and made some valut with file. And I installed Obsidian Git plug-in and enabled it.
But It said, can't find valid git repository. please create one via the given command or clone an existing repo.
I searched issues and found check the command (ctrl+shift+i). But command said nothing.
I figured out that in my path of vault. I don't have .git folder. And i tried "git init" in command, Obsidian git recognize as a repo and works.

My curious is that, when I saw youtube and docs, there's not information that I should init git as manually. Am I missed it? Or it's just a simple process that didn't need to be described?