Theory explained in 3 parts

Newton's idea was the Earth attracts an apple, the moon attracts the tides,the Earth attracts the moon and ultimately the Sun attracts the Earth hence the 'universal theory of gravitation'. The upscale from the fall of an apple to planetary motion was done via Kepler's assertion that planetary orbital periods are loosely correlated to distance from the Sun but within Newton's scheme there are a number of things going on, most notably the attempt to connect small scale experimentation with astronomy via the 'scientific method'.