Key to the AS specification are Stalin’s economic policies. Rarely a session goes by, if ever, where the questions on the Stalin period do not require either direct discussion of an aspect of the plans or their consideration in support of a question on another Stalin topic. Simply put, the economic policies were at the heart of everything Stalin did, be it art and culture or the Purges.
The two links are for summary notes on the 5 Year Plans and Collectivisation. They are brief and will need more revision to bulk your knowledge out, but it should cover the key points.