Linking fields from one table to another

I am trying to create a database to handle customer relations.

In one table / layout the user will enter basic details about the
customer and the option for 2 locations, for example head office and
plant.

I then have another table / layout for visits to a customers site. I
want the user to select the location they visited based on the basic
customer details.

I have created 2 checkboxes in the visit layout that gets the
information from the basic customer details to display head office and
plant. When one of these options is selected I want it to save the
results to the visit table to capture this information.

How can i get this information to be stored as there is a choice of 2
separate fields from one table to be used in a single field in
another. (Right now the checkboxes are only viewed there is no
functionality for either to be selected)

Do I have to use a calculated field or is this a linking issue between
the two tables?

If someone out there can help I would really appreciate it.