Unless you are talking about doing this with code, I sense a homework
question written in only moderately obscure teacherese. In normal language,
it means open a table in Design View (click the Design button), type the
name of your field in the Field Name column. In the Datatype column, choose
AutoNumber. While you are still on that row, click the Primary Key button on
the toolbar (looks like a Yale key). A Key symbol will appear next to the
field name showing that this field is the Primary Key field of your table.
Evi