Professor Hammerhead's journal (in the Shark museum) had the translation key for the hieroglyphics. But that page is missing. You will find it on top of the ruins. You have to spell the word "open" in hieroglyphics. (see related question)
On the face by the underground door in the ruins, you need to press the four teeth that spell the word "OPEN" in the hieroglyphics. The translation page is on top of the ruins. Counting all the teeth in one row, left to right, press the 3rd, 4th, 6th, and 7th teeth, then the nose.