Importing Records Into Vertical App

Importing Records Into Vertical App

Hello...

My clients will need to import records into my vertical app.  For example, they have 150 employees and will need to import them into the system.  There are fields that are custom lookup fields that are not importing.   In doing research, I believe I saw a solution for the regular CRM in which you set the properties to "allow adding new".

I see no such option in my Vertical App.  So how is this done?  It obviously ins't an option to manually enter all of those records. 

Thanks