Its a shame that the instructions are missing. The most important part, the manufacturer of the kit sets the bar. I worked on a lot of equipment, where the installed parts were backward to USA Standards. Of coarse no instructions to go by. We had a piece of equipment fail to early in its time cycle. I changed the bearing alignment, fixed and expansion, got a normal time cycle. Got a attaboy, big deal!
The piston arrow is for end gap alignment to the port openings. I have seen pistons with no arrows. Just my luck! No Arrows, what do you do?