They would be very complicated!
If the moons lined up, you would get big tides; if they were at 90º (2 moons) or 60º (3 moons), the tides would partially cancel out. But of course it would also depend on the masses of the moons and their distances from the Earth.
If the Earth had several moons they would probably be in resonant orbits, like those of Jupiter, with specific ratios between the orbital periods. Therefore there would be a certain period after which the same configuration would recur, and so would the same tidal conditions.