As you can see from the screenshot above, this is a fairly simple program to use. All you have to do is provide it a spool request ID.
I will use the standard SAP delivered program "Entries and Leaves" (transaction: S_PH9_46000223 - EEs Entered and Left). Upon executing this transaction, I will get an ALV format output. Normally I would export this to MS Excel, however let say I would like to produce a PDF format instead.
From the menu bar, I would select List -> Print
Upon printing, you will receive at the bottom of the screen a "Spool Request"
Using the spool request number, you would enter it into the program and execute. It is that simple!