What's the best way to learn what each seasoning is?
Spices can sometimes taste different when their context(other spices and foods) or preparation is altered.  Other than trying known recipes, I occasionally taste an unfamiliar spice in several states over a period of time:


raw in cheek for a little while
Infused (like tea).  Try some plain, some with salt, and some with sugar, (an acid like lemon juice or vinegar may be a third option).
Cooked and raw with a grain like brown rice. Try some plain, some with salt, and some with sugar.
Cooked and raw with meat.


Some spices have surprised me, such as turmeric, which was familiar to me with savory dishes, but which I had never previously tried with sugar.  Some spices taste about the same everywhere raw or cooked but you'll find new uses, like cinnamon in broth, while others will only be useful cooked or uncooked.