This worked, oh my goodness!!!! I am so happy, thank you so much. For anyone else who reads this, what you have to do is:
Make sure you have the file that you're trying to upload ready and finalized, because you'll have to re-do all these steps every time you update it
Open the "Create New Page" menu in the "Pages" section of the Squarespace editor. Scroll down to the "Other" section, and selected the "Link" option
Don't type anything yet, but click right on the gear icon
On the left, click on "File"
Scroll down, click "Upload File" and select your file, (after u