excavation area 2nd part of Alabama Smith:Escape from Pompeii

I cannot find the "hole" hinted at in the "help" prompt--also don't know what to do with the symbols hinted at on both sides of the archway at the excavation site. I have a key, a magnet, a bottle of glue, a ring, and a bowl of dampened cl;ay in my inventory. It seems that the ring is supposed to go inside the hole, but cannot find the hole and don't understand how the other items fit in. Any help out there?