Hi Steve,
Would this just need to be creating the measure group in SSDT? If you're creating a warehouse and then populating it with data, before creating a new cube in SSDT it sounds like a bigger article with a number of sections:
1: Creating the data warehouse (creating dimensions and fact tables, assumption would be that the ETL has been taken care of)
2: Creating a new SSAS solution in SSDT
3: Connecting to a data source and adding dimensions and facts to the DSV
4: Creating dimensions
5: Creating measures
6: Creating calculated members
7: Connecting to the cube and querying the new measures using MDX and Excel
Do you have a deadline, or is it just a 'complete when you can' ?
Cheers,
Jim.