After getting the access key to the sunken ship on Myst, you find the linking book to the Stoneship Age.
Look in the Telescope
When you arrive, you are on the deck of a ship. There is a flooded door down into the ship, and behind that, there is a door going into the rock. Face the door going into the rock, then go up the stairs to the right. There is another flooded door down into the rock, and a wooden ramp to the right that spirals up the rock. Go up the ramp. At the top, you find a telescope. Look into it, and drag the view until you see the top of a building. The markings show that the building is at 135°.
Drain the Water
Go back down to the ship, and go around to where a narrow walkway leads to a small structure with an umbrella over it. There are three buttons under the umbrella. If you press one of them, you hear a water pumping sound. You will find that one of the areas in the middle has been drained of water after pressing a button. The button on the left drains the stairs leading down into the ship. The button in the middle drains the stairs leading downward from the doorway that you were facing when you first arrived. The button on the right drains the stairs leading down the lighthouse.
First, press the button on the right, then go to the lighthouse and go down the stairs. There is a wooden chest at the bottom. Use the lever on the left to drain the water out of it, then turn the lever again to close the valve. Then go back up the stairs, and go back to the umbrella. Press the middle button.
Unlock the Trapdoor
Go back to the lighthouse, where the water has filled the lower area again. Use the chained key to unlock the chest, and take the key from inside. Then go to the top of the ladder and use the key on the padlock there. Open the trap door and go up above. Turn around and you will find a generator.
Charge the Battery
Turn the crank for a while. Six or seven full rotations should be enough to fill the battery. You can click the battery on the right to see its charge level. The battery will drain over time, so you may need to come back and turn the crank again later.
Turn on the Lights
Go down the stairs that go down into the rock. If it's flooded, go to the umbrella and press the button in the middle. As you go down, you will pass some metallic archways. On the side of one of the archways, there is a small door on the side with a red mark in the middle. Click it to open it. Go into the room and go to the end of the passageway.
At the end, you find a compass-like device. There are buttons all around the edge. This may remind you of the telescope at the top of the rock, if you looked through it earlier. Rotating that telescope showed you the degree at which the lighthouse is located. You need to push the button that corresponds to its degree: 135. This is the same as southeast on the compass, so click the button where the compass points southeast. If you click the correct button, underwater lights will come on. If you click the wrong one, the lights will go out, and the lighthouse battery will be completely drained, so you will have to go back and crank it up.
Get the Red or Blue Page
Once you have clicked the correct button on the compass, go back to the stairway and go down to the bottom. Note that there are two walkways leading away from the compass room, and two stairways leading down into the rock. One of the stairways leads down to Sirrus's bedroom, and the other leads to Achenar's. You will find a red page in a drawer in Sirrus's bedroom, and a blue page on Achenar's bed.
In addition, in the drawers in Achenar's room, there is half of a torn note that you may wish to make a note of.
Return to Myst Island
Once you have pressed the correct button of the compass and turned on the underwater lights, you can go back to the umbrella, press the button on the left to drain the stairs down into the ship, then go down those stairs, push the button on the door at the end to open it, and go down the stairs to find a table. Click the table to make the Myst book appear. You can go back to get the red or blue page if you don't have one with you, and you can come back and get the other page later if you wish.