Question about populating fields on a form automatically.

Question about populating fields on a form automatically.

Hello,
 
I have created a form called for employee contact information, that has a user's name as well as the branch that they work at and other info.
 
I have also created another form and I have it set up so that I can select the employee's name from a drop down last as they are created, but I would like to know how to have it populate a field with their branch location when their name is selected.
 
Thanks.