I have done this before multiple times, but I don't know how, and I'm unable to figure it out for the N-th time.
I have a facebook app that I created, in the form of several nodejs scripts, which posts on behalf of several Facebook pages that I own (and created). Now I have created a new Facebook page, and I want to write a new nodejs script that posts content on (and as) the new page.
Somehow, in the past, I was able to get an access token for the app to post on each page. In my old nodejs scripts, I use those access tokens. I have already tried to use the same access token to post on the new page, but obviously that does not work, as the access tokens I have only allow my app to post on those specific pages. Just to clarify, the old scripts using the old access tokens still work to this day and are currently posting daily on the old pages.
I go to https://developers.facebook.com/tools/explorer but I can't figure out how to generate the access token that I need.
I have this:
but the new page doesn't show up there (as don't several other pages that I own), so I'm lost.
Here: https://developers.facebook.com/docs/facebook-login/guides/access-tokens#pagetokens
it says:
To generate a page access token, an admin of the page must grant your app the Page permission or permissions needed. Once granted, you can retrieve the Page access token using a user access token with the required permissions.
I am an admin of the page, so I seem to understand that I, as a human being, through a normal GUI, need to somehow grant the app permissions to manage the page. However, I have looked everywhere and been unable to find out how to do that. When managing the page, I can't find anything anywhere related to apps. When acting as my personal profile, there is an app permissions section very well hidden in settings (which is not accessible when I switch to a page profile), but not only it does not mention pages, my app doesn't even show up there.
So how do I give my app the permission to post on my page, and (if that's a separate thing) how do I get the permanent access token that my script can use to do that?