Go to mpcautofill.com. At this point you have a decision to make about what sort of art/cards you want. Click on the "Select Drives" button and select the drives that have the cards and art style that you want.
If you are looking for every standard card, with the right set symbols and no proxy-text berndt_toast83 is the only name in town. I recommend including his drive no matter what to fill in any cards that other drives might not have.
If you have no clue just leave them all selected.
Once you've selected the drives to search paste in all of your quantities and card names from your excel spreadsheet.
The review page allows the selection of card variants. Go through each of the cards and select the variant that you want.
Once done selecting card variants review everything on the right hand side. Select your card stock, I recommend (S33) Superior Smooth. Next select your card back. Lastly, click on Generate Order.
Move the downloaded XML file into the same directory as the autofill.exe. The folder should look like this: