How canone use Hardy-Weinberg principle of genetic equilibrium to determine if a population is evolving ornot?

Does the population meet the requirements for H-W equilibrium? If not, then the population is evolving.  H-W equilibrium means there is no change in allele frequencies over time. Evolution is defined as a change in allele frequencies over time.

However, the unlikelihood of HW equilibrium does not preclude relative evolutionary stability. It just means there are likely to be small evolutionary changes from generation to generation, those changes may counteract each other. For instance an increase in one generation of a less adaptive allele due to genetic drift may be counteracted by a subsequent decrease in the allele due to natural selection.

LOL.  You need to use the equations.  The principle is just a statement that allele frequencies tend to remain the same unless something is occurring to make them change (which sounds like something Captain Obvious would say).

You do a census of the population noting how many have the dominant trait and how many the recessive for the characteristic you're interested in.
Then you plug those numbers into the Hardy-Weinberg equations:
p + q = 1
p^2 + 2pq + q^2 = 1

If you end up with something that isn't really close to "1" on the right side, then your population is undergoing evolution with respect to the gene you're studying.