How do you start a tree with the seed at the top of a palm tree?

Generally, it's an effort. You have to remove (called scarify) the outer layer, and then provide a moist, warm, somewhat humid environment, and then allow the seed to develop. Every seed is different, but mostly they need to stay connected to the seed shell upon development for a certain length of time, as it is an umbilical chord of sorts. Fungus and blight can be problems, particularly in certain species.