Is it possible to insert different information in different pages, to a blank text box(s), applied in a Master Page? If so, how? Or does each specified page just have to be a duplicate Master Page of its own?
Any insight is much appreciated.
I think you have to learn the concept of pages, masters and layers.
On a master you need to place objects which are repeating on each page but not are any kind of content. On the master belongs a text frame with the marker of the page number, section marker, living headers, background, all on different layers.
Only if you have created primary text frames they have to be on the master, other placeholder are not suppoesed to be on the master.
On the page is everything which is part of the content.