How to secure Linux-Dash app with a password?

hey guys and girls
the linux-dash app is wonderful - problem is, that it has no password protection whatsoever.
Because of this I want to password protect it via a htpassword file or another solution with the same effect.

There’s a little tutorial on digital ocean exactly about this topic (see here!, but it’s not that clear for me how to achieve that for linux-dash only and not the whole yunohost installation.
I’ve generated the htpasswd so far, but I don’t know where to put
auth_basic “Restricted”;
auth_basic_user_file /etc/nginx/.htpasswd;
There’s nothing inside the sites-available folder, so maybe it’s in the conf.d folder?

And how do I configure the password auth just for linux-dash and not for the whole installation?

From what I understand you should paste these lines in /etc/nginx/conf.d/domain.tld/app.conf.

But as I can see here only a single user is allowed to access the app, so whats the point of having a password?

Ah I didn’t know that! Ok - scrapped that idea immediately.