How to map contact grid to leads page and make a connection between them

In leads page add a contact  grid and make a connect to the leads page . if i assign to a different person the lead alone is assigned to the person not the contacts related to the leads.How to change this flow in CRM2015 onpermises.

I  did all but while assigning the contact details are not assigning give ma a solution how to change the  flow of leads and assign the contacts to another user.