By e- mail they told me that yes, it is an expansion, but did not explain how do i validate the game and then use the expansion. If a different activation key is required, where the find?
...Yes, you need 2 codes:1. Game activation code (must be used first)2. Expansion activation code (optional)It's not possible to use only the expansion code and was never possible.Usually the code can be found in email. It may depend on how/where the code was purchased: there are many sellers/resellers who may use different delivery methods for codes.