Forumium uses the TALLkit Filament that integrates many tools for rapidaly building beautiful TALL stack applications, designed for humans.
So all you will need to use the administration section of the Forumium platform, you will find it in the Filament documentation https://filamentphp.com/docs.
One thing you must know, only the users with the Admin role in the Forumium platform, can access the administration
To access administration section of Forumium, you need to login with an administrator user then visit the url: /admin (e.g. http://localhost:8000/admin if you are using the integrated Laravel server to serve Forumium).
Or, simply visit the /admin url, then the application will show you a Login form if you are not already logged in.