Autodesk Revit Architecture

[#1]

can someone explain to me how underlay works? i am trying to align some of the basement level interior partions with the interior partitions at the first floor, however i cannot see the basement partitions as an underlay while im working on the first floor. all floors above are fine, i can refer to floors below to align some of the walls. ive checked the view range and all floors are set to 7'-6" top and 4'-0" cut plan. it seems to be some sort of underlay setting that is off and i am not aware of. ive attached an image showing how i am able to see the partitions below as a reference for the floor above. i have the first floor level by default at 0'-0" and the basement level at '-9-0". anyone has any ideas please share the knowledge.
thanks

[#2]

The same way it worked for you on the second floor displaying the first floor as an underlay, should work for the first floor and the basement levels. Is it possible that the that the underlay orientation property/parameter is set to reflected ceiling plan instead of floor plan in the View Properties dialon window?

Mel Persin, aia

[#3]

thanks much, Mel.
after posting here, i kept messing around with the software and finally i realized it was a underlay setting, the same axact setting you mention.
i was suppose to go to the first floor level and select the basement level as an underlay.
thank you for the quick reply.
have a great one.