Hi @NoorMohd,
Without more information it's is hard to advise on what all the possible option would be, however, assuming you need a Input Value Parameter type to be updated by a user to determine how the main dashboard will show (or even what dashboard to show), you might want to consider creating a simple initial dashboard that allows the user to update the parameter and an OK button that would set the parameter and open the main dashboard (via the Navigation Action -> Open Page).
