How to calculate sales per quarter with DAX

[Lautjelief]

Im trying to make a graph that only shows the sum of sales between each quarter. The periods start and end on the 26th of jan, apr, jul and oct. This is the result Im looking for (excuse the questionable Paint skills)

Ive tried doing this by using the window function, but it just gives me the output of the future, not the past. Also I cannot seem to figure out how to set the period start and end date to the 26th. Here is my DAX measure:

SUMX(
WINDOW(
1,ABS,
1, ABS,
SUMMARIZE(ALLSELECTED('[DIM] Date'),
'[DIM] Date'[Year],
'[DIM] Date'[Quarter]),
ORDERBY('[DIM] Date'[Year], ASC, '[DIM] Date'[Quarter], ASC),
DEFAULT, PARTITIONBY('[DIM] Date'[Quarter])),
[Total sales])

What am I doing wrong?? I watched countless videos but still cannot figure it out

[amitchandak]

@Lautjelief , This will give sales of qtr for each date or month

Last QUARTER Sales = CALCULATE(SUM(Sales[Sales Amount]),DATESQTD( ENDOFQUARTER(dateadd('Date'[Date],-1,QUARTER))))

Power BI — Qtr on Qtr with or Without Time Intelligence
https://medium.com/@amitchandak.1978/power-bi-qtd-questions-time-intelligence-2-5-d842063da839
https://www.youtube.com/watch?v=8-TlVx7P0A0

Time Intelligence, Part of learn Power BI https://youtu.be/cN8AO3_vmlY?t=27510
Time Intelligence, DATESMTD, DATESQTD, DATESYTD, Week On Week, Week Till Date, Custom Period on Period,
Custom Period till date: https://youtu.be/aU2aKbnHuWs&t=145s