Auto populate information based on a Lookup field

Auto populate information based on a Lookup field

Hi,

In the Contacts Module I have:
  1. A custom field named First Name
  2. A custom field named Last Name

In the Deals Module I have:
A lookup field named Contact Name
A custom field named First Name
A custom field named Last Name

When I create a new deal and select a contact in the Contact Name field, I would like the First Name and Last Name fields (in Deals Module) to be auto populated with information from the same fields in the Contacts Module.

Could I get an assistance on a Deluge script for this please?
Thanks in advance