Here's a breakdown:
* As a proper noun: When referring to the region or people of Scandinavia as a whole, it should be capitalized: "Scandinavia is a beautiful region." "Scandinavians are known for their love of nature."
* As an adjective: When used as an adjective to describe something related to Scandinavia, it's typically lowercase: "Scandinavian furniture is often minimalist." "She has a Scandinavian accent."
* As a general term: When used in a general sense, not referring specifically to the region or people, it's usually lowercase: "The store sells Scandinavian-style furniture."
In doubt, it's always safe to capitalize it.
Let me know if you have more specific examples and I can help determine the capitalization.