Once you have gone to any Your Sanctuary locations that you hadn't been to before, you're ready at this point to head on to Scaraba. To get there, you should talk to the sailor in Toto, the port town of Summers. He'll bring you on board, and you'll sail across the sea.
During your journey, the Kraken, a giant sea monster, will swim up to your boat and attack you. Find out how to defeat Kraken.
Once Kraken is dead, you will continue on to Scaraba. In town, the sand is not too hot, but outside the borders of town, you'll sweat and be at risk of sunstroke, so beware.
The locals will mention the southern pyramid, so that's your next destination. However, be sure to check out all of the shops here. Also, talk to a guy sitting on a rope to learn about Dungeon Man, and the need for a key to get into Dungeon Man.
One of the local shops sells the Piggy Nose. This item can be used in a place you'll reach later, where there are Magic Truffles hidden around. The piggy nose will tell you when a Magic Truffle is close by. Magic Truffles restore a lot of PP, and they're very rare, so pick up the Piggy Nose now, because you'll definitely want it later.
Near the southern gate of the Scaraba town, you might occasionally run into the Master Criminal Worm. This enemy gives a huge amount of Exp, so always go fight it if you see it.
At any rate, head south from the town, and you will eventually reach the Sphinx, who guards the pyramid. In front of the Sphinx are five switches. These switches match the pattern shown on the hieroglyphs that you read in the museum. The pattern is also in the Hieroglyph Copy, which you can check if you want to. But the pattern is shown below. The way it works is to start and end at the dot, going to the other switches in numerical order:
. 4 3 2 5
When you step on the top switch, the Sphinx will speak to you. After that, go to 2 in the diagram and continue from there, ending at the top switch. Each time you correctly press a switch, a musical tone will play, with a higher note playing each time. When pressing the final switch correctly, a brief tune will play, and the pyramid door will open.