Molecular equations and structural equations, differences?

the molecular equation of a compound is its constituent atoms reduced to their simplest ratios. Its structural formula is a description of its functional groups and where they lie in relation to each other so for your 3-methyl-1-butanol example it has say for example (I'm not bothering to look it up so this is only an example) C3H8O whereas its structural formula explicitly describes the functional groups OH and methyl (CH3) and where they exist on the carbon backbone hence the 3 and the 1 so would look something more like C2H4CH3OH again this is just an example of a structural formula and is NOT correct for 3-methyl-1-butanol except by blind luck