Access Form with lookup data

[mikie15]

I have created a form in Access to use to populate a table. A couple of the fields have a lookup table. There is a table with Territory number and salesman name in it. On the the form there are the same two combo boxes, but I want the Salesman box to be populated with the salesman name that handles the territory that is inputted from the lookup table.

I know I can do this but I need help figuring out how.