@Ambersimone06 , if you’re using a Mac you can print to PDF from any app including your browser. For Windows there are several PDF printer drivers available, many are free. A quck search brought up this URL:
If on a Mac, for each lesson you bring up in your browser, use the “reader” on the left in the URL bar (4 horizontal bars). This will remove everything else from the page except the lesson content, which you can print to PDF.
You can assemble each page in the Preview app to create a single pdf file. You will need to build your own table of contents of course. Let me know if you need additional instructions (for Mac only).