Prepare
Trim marks drawn from the page boxes, on a sheet that grows only as much as it needs to hold them. Length and offset are yours to set.
Marks sit exactly on the trim read from the file, not on a guess.
The offset keeps marks clear of the bleed so the cut never clips artwork.
Adjust both in millimetres under Adjust.
The defaults come from your file. Change a setting and the proof updates before you let go of the mouse.