In the Criteria row under your date field, enter:
Between [BeginDate] And [EndDate]
That should work, but it is a good idea to declare these parameters. Choose
Parameters on the Query menu, and enter the same names, specifying the data
type as Date:
BeginDate Date
EndDate Date
As an alternative, you can tell use a form and get the query (or report) to
pick up the dates from the form. Details: http://allenbrowne.com/casu-08.html