Question

How do molecules and compounds related to each other?

Answer 1

All compounds are molecules.
However,
Not all molecules are compounds

Explanation:

A molecule is two or more atoms chemically bonded to each other.
Whilst, a compound is at least two or more different atoms bonded to each other.
E.g.

H2 is a molecule since it has two atoms
But not a compound since they are the same atoms.