The below gives some insight into what it takes to understand scent material. It's an adventure, and a perfumer makes these observations nearly daily.
Use your nose, smell and take many, many notes.
Build a personal, close relationship with this particular material.
You should know how strong these materials are compared to all other materials.
You should know what makes this material different from all others; for example, linalool and bergamot smell somewhat similar, but they are also very different! In your own words, you should be able to describe what makes a particular material different and unique - even from materials that resemble it!
You should know precisely how long this material lasts.
Write down if this material reminds you of your grandmother's basement.
The goal is to craft a personal, significant and unique relationship with your scent materials!
What are the various scent facets found within this starring material?
In the example of rose otto, I know (from experience) that the following facets are found;
Juicy lychee - Some roses possess a tropical, fruity lychee aspect, and I love it!
Ripe cherries - Some Rose De Mai Otto possess a fantastic deep, powdery soft cherry facet!
Green and red apples make total sense because apples and roses are very closely related to one another.
Lemon - some roses possess a sharp, lemon, nearly green metallic top note.
Slightly powdery - I have often said, "Flowers are just powdery fruits."
Slightly waxy (much less waxy than rose absolute) - even rose otto has some soft, light, airy powdery texture. It's nowhere near as waxy as rose absolute, but it IS soft around the edges.
Dark honey delightful - yes! A depth of jammy, ruby-red sweetness is nearly indescribable in rose Otto.
Jammy, overripe strawberry - yes! Again, rose otto has this jammy, deep, highly concentrated sweetness that no other natural material has. It's truly, genuinely unique!
Slightly green apple/tart pineapple - yes! The top notes in some rose otto can be somewhat sharp tropical green. No doubt!
Question: Where do I find, see, or how can I recognize these facets?
What are some adjectives I would use to describe this starring material?
How do other people (usually found online) describe the scent of this starring material?
Use these sites to see how others describe any given scent material
What are the central, chief molecules found in this starring essential oil or absolute?
Use Google to search "chief molecular constituents " in "rose otto."
Results here: https://en.wikipedia.org/wiki/Rose_oil
The above gives some insight into what it means to understand scent material. It's an adventure, and a perfumer makes these sorts of observations nearly daily.