Beginning Data Warehouse Design I am beginning to develop a Data Warehouse. The data does not already exist in a relational database. Instead it will be sourced from various 3rd party vendors.

The data requirements have been drawn up into an Excel spreadsheet containing 15 sheets with column totals ranging from 5 to 60 on each sheet.
Do I create a Fact table of each sheet heading and within each sheet create related dimensions.
In the sheet with 60 columns, none look like they can be grouped into separate dimensions. So do I create one very large dimension?

Also, all dimension columns will have default values, which can be overridden for a specific related fund. How best to do this? Type 2 SCD and add the fund identifier to each dimension?

Thanks!
Your question is too vague and general to get a good response here. What you need is a text (El Masri or Garcia-Molina or Connolly) to explain the basics of RDBMSs and of data warehousing.  

Forums like this one are more about smaller particular problems than broad stroke questions like this. Read a text, google. The only tip I would give you is that you should have a good grasp of the basics before going on to DW systems.  

There's a time and a place to depart from the rules of normalisation - and don't forget to test with realistic data.