More prefill Questions

I have more questions pertaining to fields in a form that I want to prefill.

Mr. Vinson was helping me and suggested that I needed a combo box, which
would be great if I knew how to get that combo box to do what I want it too!

I have my tables built and would like to start on my form--in the form I
will have (among others) the following fields:
AccountNumber
Distributor
Job
JobAddress

When I pull the AccountNumber up--I want the Distributor field to prefill
Once the Distributor Field is prefilled--I would like the Job field to
recognize that this ditributor has 2 Job addresses which I can select Job 1
or Job 2
Then I would like the JobAddress field to prefill from the selection.

So far I can only get the AccountNumber field to work correctly--because
it's from a lovely drop down box based on the CustomerAccounts Table.
I also have a Branch Table which is set up like so:
Account # Job # Job Address
21000 1 First Addresstown, somewhere
21000 2 Second Addresstown, somewhere Elseville
21001 1 First Addy for this Account, Yonderways
etc...

Mr. John Vinson helped me to set up the Tables correctly and now I need help
moving forward with the form building.
He stated that I would need text boxes with Contorl Source properties--can
someone hold my hand and walk me thru this?
Any help is GREATLY appreciated it!