count picture item
(2) Panasonic 8k Projector
asset serial number
into a sub summary layout part (see the Part setup dialog for adding this) "when sorted by" your item. The (2) can be produced from a "count of" type summary field. When you place it in a sub summary part, it computes a sub total based on the records grouped below/above that sub summary part.
Your records must be sorted in a sort order that includes the sub summary part's break (when sorted by) field or the layout part will not be visible when you are not in layout mode.