What is the easiest way to explain molecular compounds and covalent bonds also adding information about valance electrons? Thanks

Molecular compounds consist of two or more nonmetals. The nonmetals that make up a molecular compound are held together by covalent/molecular bonds. Covalent bonds is known as the "sharing" of valence electrons between two or more chemical species. Valence electrons are shared so that the atoms of the compound can become stable, much like how ionic bonds transfer valence electrons between atoms to achieve stability.

petroleum? coal maybe?