How to get to 'Advanced' tab in power pivot window:
When in PowerPivot window - click on the icon left/top under titlebar-- there should be a drop down that allows you to switch to the 'advanced mode' view tab. I find this most useful for the managing 'perspectives'. I create two perspectives 'CORE' for tables that require regular updates and 'LKUP' for those tables that remain mostly static over time. I then use AutoIt scripts to refresh the 'CORE' tables.