How to specify form UI elements as input and output parameters

Hi Experts,

I have created a form in which i have 4 UI elements, for one UI element value comes from BAPI, so i have connected BAPI to form input, but while deploying its giving an error,bcoz no input parameters for the form. how to specify the UI element as an input and output parameters for the form.Can any one please help me out in this.

Regards,

Prasanna