So, it is something like -> "на основе" or "на основании" новостей, right?

Why is it на новостях (locative)? Why not на новостям (dative)?

By the way, I saw "на сообщения о" phrase used the same way so it is the same "на" preposition like in "на новостях" phrase, isn't it? But "сообщения" is singular and "новостях" is plural.

Does "сообщения" and "новость" mean the same thing? They both mean "news"?