When these terms are used, light is been pictured as an electro-magnetic wave.
Thinking of the microwave example, inside what you would have is like a sea where light is equivalent to the undulations. So in this picture, the wave-length is the distance between two consecutive wave peaks. Larger wave-length implies more separation between these peaks.
Also the relation between wave-length and energy is also very similar to the sea picture. Large wavelength implies the "push" you get from several waves takes is more spaced, hence you receive less total energy per time interval.
On the contrary when the wave-length is shorter, you receive the "pushes" more frequently, i.e. they are less distanced from each other, and coming one after the other more rapidly, and the transfer of energy is higher.
Finally, to clarify the classical view of light: it is an electro-magnetic wave, that is a self-sustained oscillation in space an time of electrical and magnetic fields, each of them generating the other and propagating freely through both media and vacuum.
Clarification from comments:
The concept of light as EM waves is not reconcilable with the concept of photons. Those are two views of light which are incompatible. If you are trying to understand what light is, well in short we cannot explain it in layman terms so far. We can say that in some phenomena can be explained using the photon description but not the wave description, and others the opposite, while some can be explained by both. We have equations which gives us a complete explanation of these phenomena, but explaining them in layman terms is not easy, because in these equations light is neither photon nor wave, is just a physical entity which follows this equations but for which we don't have a simple conception, not as simple as photon or wave conceptions are.
