Designing Outlook form

Hello,

I have two drop down menus, one called 'Floor' and the other called 'Area'. I want it so that when I select a type of floor, it will dynamically update the area drop down with relevant items. Can someone please show me how to link them?

An example would be

Floor
Values =   Basement, Ground

 
If Floor = Basement    

then values in Area should only display:  Bike Store, Kitchen, Boiler Room

If Floor = Ground
then values in Area should only display: Reception, Lift Lobby, Library

Please see attachment for a basic visual.

Thanks
image001--1-.png