Basicly
You won't "link" the parameter to any field in the report, you will need to use the date parameter field to limit ( restrict) the result set of data that you are working with.
if you are working with data that comes directly from the tables, you can to use the Report Select Expert ( from the Report menu dropdown ) to create a formula that says essentually .... Give me all the data where the start time date is greater than the date value of the Parameter that begins the range wanted ( and is less than the ending date range if you have one ) or if you are working with a select statement or a command to retrieve your data you can incorporate the parameter into the select command just as if were a regular field. and the same if the data source is a stored proceedure or view.
Ted