Unique Customer Count

Hello Gurus,
Lets Discuss one common challenge in these days of finding unique Customers purchased in the specific time frame.
Let's do the challenge.
For each month, how many unique customers have purchased in the last six months?

Step 1:

Create  3 calculated fields “6 Months Buffer”, “Index=1”, “Rolling CountD”  by below formulas.

Step 2:

Drag and drop “Order Date” date dimension field into columns shelf and change format as discrete date part “Month/Year”.

Step 3:

Drag and drop “Rolling CountD” calculated field into rows shelf, right click on “Rolling CountD” field, click on edit table calculation and select specific dimension as customer name.

Step 4:

Drag and drop “Index=1” calculated field into filters shelf, select “True” and make sure addressing as customer name.

Step 5:

Drag and drop “Customer Name” field on details of marks card.

Thanks Gurus,
Prazval.ks