You're welcome.
I know these things can easily get to feeling like they're overwhelming, but if you take them one step at a time you can get through it. If you know someone close who is savvy ask them to assist. 🙂
May I ask how many stories or documents you hope to present to your printing service?
Do you now have these document files collected in one location on the drive - in a single folder?
This would be step 1.
Did you speak with someone who told you the files need to be in pdf format for printing?
If so, can you contact them again and ask if there is a particular type of pdf format they require?
That will be step 2.
Step 3 will be converting the documents into an acceptable format - the format that your printing service requires. As VikingOSX has posted, PDF/X format might be required, but you can tackle that when you get to it.
Will wait to hear back from you.