After the Prince Buffoon helps the goblins shrink, they explore a desk.
Get a Shard of Glass
Have 
Fingus take the match. Have
Winkle use the match on the eye in the skull.
Have 
The Buffoon click the eye.
Take the shard of glass that broke off of the glasses.
Get the Bookmark
Have Winkle stand to the left of the knife.
Have Fingus click on the handle of the knife, then have
Winkle click on the point of the knife. They will move
the knife closer to the book. Then do it again so they move the knife even
closer to the book. Then have Fingus click on the bookmark
to cut it off with the knife. (If he just says something instead of cutting
off the bookmark, have Fingus and Winkle move the knife again, then have Fingus click the bookmark
again.)
Plant a Seed
Have Fingus use the bookmark on the candle.
Then have Fingus use the glass shard on the ray of light
coming from the window. This will light the candle. Take the wax that falls off
of the candle. Use the wax on the seal in the letter, and you will get an
imprint. Use the imprint on the keyhole in the box to the right of the map.
Take the seed that falls out of the box. Have Fingus use the seed on the village in the map. Have everyone click on the vine
to go to an area outside the village.