Hey @Wallace_White welcome to the community! You’re right there are some legends on here 
OK so I think your issue can be solved by adding another column to your Orders table which counts the number of orders by customer on each line:
thisTable.Filter(Customer=thisRow.Customer).Count()
Then you can sort the grouping by that column.
The cool thing about the community is you’ll probably get a few more (better?) answers too! Good luck.