pretty sure the 2 trays mount the bren mag boxes on the r/h sponson and side plate behind the driver. the small open ended box looks like a starting handle mounting and goes on the rear shelf. not sure about the tray with the cutouts and I don't know what the weapon mount was used for but could be Vickers, piat or mortar.
are you restoring a carrier ?
all the best
Currently respraying. It's a Mk II* however, and it came with these parts which we couldn't ID, presumably because they're MK I parts.