MDE- Who defines the screens for mobile data entry?

hi all,

I am aware there a many posting about Mobile data Entry and setting up menus, profiles, barcode type to warehouse, etc based on IMG.

I am new to these and want to know if defining these type of steps in IMG for MDE Will SAP provide
the screens where the fields during the scanning of process?

or an abap guys is needed to define the screens that will display on RF device (gun)?

thanks

neo