Chainsaws

many technical issues to abide when doing the top-end.  adhering strictly to these rules will afford you many years of good compression.  the 3 most important considerations;  use a heavy weight lube oil on the needle cage bearings before re-insertion into the push rod.  make absolutely certain of complete seating of both circlips,  triple check for total smoothness and work out any roughness or minute ridges in the sleeve.  and always chock the piston solidly for roller rod extraction and installation so you do not put any torque on the crank rollercage bearings.

and once again, Eugene is correct.  arrow universally points forward on the piston.  one should thoroughly clean any skin acids from the rings, piston and sleeve before re-installation.  use of surgical gloves is a great idea.  and I highly recommend you coat the entire top-end with a capful of jaso into the plug seat after it is back in 1 piece.  slowly pull the crank around several rotations to ensure distribution.

I have every confidence you will make a good fist of it...  good luck...