3D Models in Unreal Engine

Hello everybody,

I downloaded about a week ago unreal engine. As a team we would like to create a virtual museum for the university. For this I got the order to download the 3D models.
Now

I have the problem that I initially do not know which files I have to
download all, so that it is displayed correctly in the unreal engine or

How can I assemble the downloaded models in the unreal engine and then export?

I would be glad about an answer and help.

Thank you very much.