So, what are the traditional Skandas? Like all things in traditional Buddhist Philosophy, it depends which philosopher you ask. Philosophers disagree on the details. But, basically, you have:
1-Matter: The "stuff" (we might say atoms and molecules) that are the world (and your body) and exist without regard to whether your sentient mind is perceiving them or not.
2-Sensations- The sensing of the matter by the sense organs. These sensations are soon interpreted as pleasant, painful or neutral (we now know that, much as primitive Buddhist psychology described, much of that judging goes on even before you perceive the sensation. For example, the brain knows pain and danger even before you more deeply or consciously perceive that you are touching a hot stove).
3-Perceptions- Your mind perceiving, inside the brain, data from the senses. You become aware of the raw, incoming data inside your brain.
4-Mental Formations- Now your brain does all the complex processing, interpreting, organizing, reacting and responding to the data. You give it names, think about it, form opinions, likes and dislikes, moral judgments, have emotional reactions, formulate responses, and actions. etc. You do all the stuff that your brain (and any animal brain, though humans do more of it) does in interpreting, thinking about and acting in the world.
5-Consciousness is that extra thing that makes you alive. You are not merely a computer processing data (or a simple insect brain), but are self-aware, alive. The closest example I can give you, perhaps, is a new born baby that at first, cannot interpret the sense data beyond basic sensations like "pain" "pleasure" "hungry". Only gradually does it develop a more complex interpretation of the world, for example," this is my hand, this is my foot" (baby's actually have to discover this), "they are part of "me", the crib is not "me"" etc. A complex world view starts to develop and, only then, does the baby become "self-aware" and conscious of itself as itself (it probably was not self aware until that time, and was just raw experiencing. Now, the baby is aware that it is "me").