How to add admin page for plugin?

I’m using Bitbucket and want to create a plugin with the ability to apply it to a specific repository.
I want to add a separate page for plugin settings. My goal is to learn how to apply the plugin only to certain repositories (not to all at once)
If I understand correctly, you can use Web Panel for this purpose.

The documentation says that the location parameter is responsible for the location in which the web-panel will be displayed
To see the possible values ​​of the location parameter, you need to add the “?web.panels” parameters in the browser, for ex “http://localhost:7990/bitbucket/projects/PROJECT_1/repos/rep_1/settings?web.panels” And you will see something like that (see screenshot)

After the possible locations are displayed I use one of them “repository-settings-required-builds.badge”
I expect that my web panel will be displayed below the location repository-settings-required-builds.badge
But no new item is added (the text sticks to the existing item)

The question is how to do this?