In the lower right of the window frame, just above the text "Record Time," are three gray text boxes. The first is the current cursor, the second is the end position of a selection, the third is the selection length. Double-click in the first box and enter the desired time code and press Enter. Depending on the time format you can specify the frame number with a ";" as in HH:MM:SS;FF. You can enter time codes in the second and third boxes the same way to precisely adjust the end and length of a selection.