I think I know what the problem is, because I also didn't get instant files.
1) Open whatever file you want to upload.
5) Under Printer, choose PrimoPDF instead of your normal Printer (it has to be downloaded and installed first, otherwise it won't show on your list of possible printers
6) While you're in this dialogue box, check that your paper size is right, and then click OK.
7) This takes you back to the normal box, where you can check dpi, etc. (this affects file size -- everyone says 300 dpi is adequate for scanned files, so 600 probably just wastes space?)
9) Next, you'll see a box that says "Sending music to printer".
This is where you have to be patient. After another 20 seconds or so (initially i didn't wait that long), a PrimoPDF box comes up. Here you type a path and file name under "Save As", and then click '"Create PDF" (at the bottom of this box). Only now do you get your PDF file under the file name you chose. If you don't do this part, I don't know where it sends the file, or whether it creates it at all, but it's like it went into the ether when it "sent music to printer" . . . . . . .