Kepler's 1st law: Each planet orbits the sun in an ellipse with the sun at one focus. An ellipse is an oval or flattened circle shape. Kepler placed the sun at one of the foci of the ellipse. (Foci is plural for focus). Kepler's 2nd Law: The line joining a planet to the sun sweeps out equal areas in equal times as the planet travels around the ellipse. A planet moves with constantly changing speed as it moves about its orbit. The fastest a planet moves is at perihelion (closest) and the slowest is at aphelion (farthest). The planet moves faster when it is nearer the Sun and slower when it is farther from the Sun.
Kepler's 3rd law: The square of the total time period (T) of the orbit is proportional to the cube of the average distance of the planet to the sun (R).