From a dimensional modelling and data warehouse design aspect, I'd read up as much as possible about the Kimball methodology:
https://www.kimballgroup.com/
http://www.sqlservercentral.com/blogs/microsoft-business-intelligence-and-data-warehousing/2012/04/08/the-kimball-approach/

Tutorial for SSAS:
https://docs.microsoft.com/en-us/sql/analysis-services/multidimensional-modeling-adventure-works-tutorial

Tutorial for PowerBI:
https://github.com/MicrosoftDocs/azure-docs/blob/master/articles/sql-data-warehouse/sql-data-warehouse-get-started-visualize-with-power-bi.md