How to add authorized applications

What I want to achieve (Authorize slack):

Question: How could I add slack as my authorized applications? Thanks!

BTW, I did try to install the slack app at – https://slack.github.com/, but after checking the setting, the slack app is still not showing up.

What I have seen( No action item or guide):

Oops, new user could only have one image attached…here is another image from reply…

Hello @HaoyuHouzz and welcome. How are you going?

I’m very curious to know what happens after you visit https://slack.github.com/ and then click Add to Slack

It should take you, here:

Is this what you see? I would hope so! Once you login to your Slack instance, what happens? Do you notice any errors elevated in the browser?