Most organic compounds are made up of collections of molecules.
Molecules in turn are composed of ordered arrangments of atoms. As a very simple example, water (shown below in various representations) is made of two atoms of hydrogen (H, white but they look pale grey in these images) each connected to oxygen (O, red):

As an organic example, acetaminophen, a common over the counter pain killer, (shown above with bottle, pills, pure crystal sample and in various representations) is made of a specifically ordered collection of eight atoms of carbon (grey), two oxygen (O, red), one nitrogen (N, blue) and nine hydrogen (H, white).

Atoms themselves are an ordered collection of various subatomic particles that we will explore next.