The path through the pyramid is pretty straightforward. As you go through, you'll get attacked by mummies, hieroglyphs, and spiders. Killing the heiroglyphs will get rid of them permanently, but the other monsters will continue to respawn in the various rooms of the pyramid.
Once you reach the sarcophagus on a raised platform, there is a door at the top left that will lead you to a Bag of Dragonite. Get that if you want, then return to the sarcophagus room and take the door on the right.
Eventually, you'll reach a casket blocking a door. Check on it to engage the Guardian General. find out how to defeat Guardian General.
Once Guardian General is gone, go into the room that it was blocking. Open the casket to get the Rain Pendant, then step on the floor tile. Return to the sarcophagus room and you'll see that it moved aside to reveal a hole. There's no going back from the hole (unless you go outside and Teleport to Scaraba to start the pyramid over again), so be sure to get treasures that you skipped in the pyramid if you want to.
When you drop down, you'll be in a room where the Hawk Eye sits on a pedestal. You might remember this item mentioned in the hieroglyphs. It is said that you need the Hawk Eye in the Deep Darkness.
From here, go through the door. The path is 100% straightforward from this point. Be sure to get the Diamond Band from the casket in the room with the hole in the ground. This is also a Magic Butterfly infinite spawn room, so go in and out to heal up. Once you drop down the hole, you might get ambushed by a bunch of enemies, so you'll be glad to have full health once you're down there.
When you get outside and start to head out from the pyramid, the Star Master of Dalaam will appear before you and take Poo away for his training. Don't worry if you gave Poo the Hawk Eye. You can get it from Escargo Express when you need it, and it will free up a spot in your inventory in the meantime.