I want to create a data entry form for my database for users to complete records and add missing data for current customers.  I would like to create something akin to a Explicit Parameter Query (a la Beginner Course 9), but I don't want to let the user type in a parameter (in this case the last name of a current customer). Instead, I want the user to choose from a list of full names (perhaps in a drop down list/combo box) already in my personnel table. [This will eliminate the option to add duplicate customer records, and prompt users to add missing data to existing records.]  I also want to add fields to the data entry form that populate various tables that include contact details. Further, I'd like to add this combo box list/parameter to the new form's header, so I can jump from record to record.  
Thoughts on the best way to proceed?