don't know how to export a suitable frame into github

[loge-dot]

hello, sorry to bother you. I'm new to the website's settings. I don't know how to use this plugin to export all markdown files into HTML files correctly. Actually, I have followed the documentation but it seems wrong with it. If I put all files into github directly, it shows the error "404 page error".
This is my export files. There is no index.file github page requests. What should I do? Is this my problem? Because my export shows a warning like this.

I've been struggling with this problem for a few days. If you can help me, I will really really really appreciate you!