Raise the sail until you see the attachment points on the leech. The first reefing point is the one near the outer end of the boom and the third is toward the mast
(the second in between). Drop imaginary perpendiculars from these points to the boom and mark them on the boom
These will be the points where the reefing lines are tied to the boom. Take the 1st reefing line. Attach one end to the outer point on the boom, thread through the block on the 1st (lowest and outer) attachment point on the leech, go down to boom end, thread into the boom (hope you have left some leading twine inside!), when the line appears near the mast, go up to first (once again the lowest) attachment point on the luff, now down to a block at foot mast and back to the cockpit
(through turning block/s on cabin
This from memory...hope it helps.
One thing more - third reef is different - as it exits from the boom by the mast it goes right down to mast base. No third reefing block on the luff. Instead there is a reefing strap that is connected at this 3rd point.