How do i import a building from maya to unreal?

Hi new to unreal and am working on a project for school. My group is making a game and ive completed most of the character ai I wanted. However im not so sure how to create maps, my friend made our map using maya and I can import it just fine in unreal.

The issue is that I cant put navigation on the floor of the map nor can my ai walk across it, I’m not sure what to do I couldn’t find many tutorials. I tried removing the floor of the map then lifting the already established floor but no luck.

thank you if you can help.