Think of atomism like music. A piano, or a bass, rather. One string. It’s nothing. It plays one tone.
You put a bunch of these strings together, and you get a piano board. Now you have more complexity, with the same string.
You add more notes at once and you get chords. More complex. Far more complex than a single string.
Put them all together in a pattern, and over several seconds, or minutes, you have a song.
One string, it’s nothing. It’s one atom. There are different atoms, like different notes. Different frequencies. Different instruments. Chords are like molecules. A bunch of atoms together are like a bunch of notes that make a chord.
A combination of chords and notes combined with tempo and rhythm and other factors can make an entire symphony. We are the symphony of the Universe. Now that’s a quote.
So when you look at everything around you, it’s easy to understand how everything is made of one simple particle.