Stand at the bottom left corner first, where the older man sits with a young body slack across his knees and doesn't look at the sea at all. Everything else moves up and to the right from there. Géricault took a studio near the Beaujon hospital and shut himself in with the canvas, and to keep himself in he had his head shaved, so he couldn't be seen in the street and wouldn't go. He was twenty-seven or so at the time. Born in Rouen in 1791, gone at thirty-two.
The timbers are the part I'd want you to look at longest. They say the Medusa's own carpenter, one of the men who survived the raft, built him a model of it to size in the studio, so the planks under those figures are planks a man remembered with his hands. In the painted gallery view attached it's the big canvas in the middle, with the visitors seated along the wall below it, quite small.
Fabien — two of the survivors sat for him as well, Savigny the surgeon and Corréard the engineer, and they told him how the raft was lashed and how the men lay on it. Actors who'd been there, advising on the set.
Fabien, the book he kept going back to was Savigny and Corréard's account, printed in 1817 — the surgeon and the engineer, both off the raft, writing it down themselves. I've had a copy through the shop once; unglamorous thing, and the dryness of it is what makes it hard to put down.