Here is a
miso recipe, and within it, it gives a good definition of it too.
The thing to keep in mind about Asian markets, is that items are often not as good quality as you would find in a co-op or whole foods market. For example you want to buy sea vegetables from Japan, not those that come from China which often can be high in mercury. Also for example miso is sold in Asian markets but it would not be the same as that in a health food store, soy sauce too.
One wants to typically buy fruit in season that is particular to ones own climate, so right now, I would eat water mellon for example, in the winter time I would not. Fruits like oranges and pinapple for example would not be something that would be considered locally grown, and are considered to be tropical . Other fruits that are considered local are apples, pears, strawberries, blueberries.
Don't worry about trying to learn and do everything at once, there are going to be a lot of both large and small changes that you will have to make. Besides cookboks, eventually taking cooking classes is a good idea too.