Example 2: Sudoc pages
When you browse the Sudoc (first example in the video), you need to search by keywords (according to your research topics). Below is an example using the keyword "serendipity".

A results list will display the first 10 bibliographic references, and page numbers will allow you to browse through the different results pages.

By selecting the first reference, the catalogue record for the book will appear.
You can add the book reference to Zotero by clicking on the "book" icon.

By clicking on the 3rd or 4th reference, a thesis record will appear, which you can add to Zotero by clicking on the "thesis" icon.

You can also try on HAL. Here again, the icon will change (journal articles, conference proceedings, books, etc.) depending on the type of document (i.e. the record) you are viewing.
The second example in the video uses href="https://scholar.google.com/" target="_blank" rel="noopener">Google Scholar. After performing a keyword search, Google Scholar displays the results (10 per page by default). The Zotero connector then displays a folder icon, which you need to click to open a window that lets you choose which references to add to Zotero.