Any resources or manuals on how it works?

I want to group opportunities by Owner (Creator), or any other possible attribute.

Not sort, but group. Let's say first we have Lost Opportunities and their Total, then Open Opportunities, etc.

Andy

I would really like to know the answer to this question as well.

This is possible but the interface for the Group By leaves much to be desired (and I made it!).

Anyways - once you've specified the data source on the group by (same way as you do a table), you set the Keypath to:
assignedTo

and the Index KeyPath to:
assignedTo.contact.cachedName

Sort uses the Index KeyPath - in the example above, it will be the user's fullname

The result kind would be:
Opportunity

You would then put a table in the group by (in the 'group by strip' in actuality).

So you are getting a list of opportunities, it is then breaking it down into smaller lists based on 'owner' (assignedTo) and then each of those small lists are displayed in a table.

You can look at the Project Pipeline Load print layout to see the Group By in action.

We definately have to improve the inspector for this element.

Where do you go to figure out what the Index KeyPath is for a particular KeyPath?