Rolling Total of Distinct Count String

Hello All,

I have a data set with Orders (String) related data that I need to visualize with a rolling sum. These Orders ID's repeat based on the number of items in the order (captured barcode scan index). I need to take the unique ID's and sum them up and show the rolling total month-to-month. FYI the same Order ID would have the same date and time repeating (as shown below).

Example data

I was thinking to count based on Captured barcode scan index = 0, but some orders would get processed multiple times (if the order fails initially). Then it would start at scan index 0 again with the same order ID.  However, the date and time would be different. But I dont know how to write that code.

The current visualization I have below is showing month-to-month values. I need it to keep going up with a rolling total and end with the current total shown

Current Graph

Expected Graph (Example)

Thank you in advance for your help.