Do you mean that http://myserver/webpage is served by a Custom Webapp, installed via YunoHost?
If so, if you want to force users to log in before accessing it, you have to tweak the permissions in the webadmin. Your app’s permission should be something like
- Remove it from the Visitors
- Add it to “All Users”
However, if your users are logged off and try to access the page, they will be asked for their credentials and will directly be brought to the app if the login is successful. They will see it in the dashboard only if they open its page.