piepiepie what do you mean by floor? Would that be a custom anchor, or a post number?
To create a table of content to title anchors, I believe we have this extension already https://discuss.flarum.org/d/31409-table-of-content
To create links to specific posts you can use the built-in mention syntax, but it doesn't show the post number in the editor, it uses the post ID instead and Flarum will create the link during rendering.
