how to use the FOR/NEXT loop and its parameters

Automation Testing question using CBTA:

In "Original Document No" in "Additional Data A" tab of VA01 that i needed to re-iterate using unique number every time i create Sales order

How do i use any command similar to For/Next loop to reiterate XYZZZZZYYY0001 to XYZZZZZYYY9999 for any future sales order creation for testing