You can open a document in three ways, by going to URL of a PDF, by opening a document via the extension, or through 'my documents.'
URL of a PDF
If you go to a local or web-based PDF (example), then you will be able to click on the extension, and the extension will see that document.
Opening a document via the extension (local document)
Click on the extension.
Click 'Open a local PDF document.'
A file picker will then display
Locate the PDF you want to open and click 'open.'
Your PDF will then open within your browser/
Click on the Blocknify extension.
Click on the menu button on the top right of the extension screen.
Click on 'my documents.'
Then all your past documents will be displayed. You can search or use pre-built filters to find the right document. Click on the document box and input your PIN to open the document within your browser.