Unfortunately I don't have time to create the solution now, but the blocker is that the calculated field is a string, so it's sorts it as a string.
You need to create the values as a date (hopefully by formatting the date in different ways) and then it will sort properly.
I'm not entirely clear on what you're looking for, are you looking on how to sort your graph by quarter and month using a timeline scale?
If so, it's not necessary to use your string calculation but to place your "order date" in the column shelf and sales in the row shelf. Make the order date 'continuous' meaning it's a green measure. This will make it on a timeline. From there I created filters for you to select the year, quarter or month. See attached on sheet 3.
Quarter and Month sort.twbx 1.2 MB
Click on the Trend Calc and select sort
Select ascending and select sort using field, select date from drop down and select aggregation as minimum
Click OK you can see the sorting happen correctly
Hope this helps kindly mark this answer helpful/complete so that it will others