hi, if i want to support the giscus

[DoMySon]

How should I change it or other ways?

[pobtastic]

This is built into Hugo, its nothing to do with this theme really - follow the instructions in the official guide: https://gohugo.io/content-management/comments/

I suspect you'll be fine adding the template line in the same place in the theme as where gitalk is (/themes/github-style/layouts/_default/single.html).