One of the first things you will notice when installing the add-on is that there will now be an indicator next to the name of the page with a count of how many unresolved inline comment threads are in the current page (although there might be multiple replies to each comment).
...
From there, you can move between inline comments by clicking on the up and down arrows within the comment window.
Next to that icon, there is an icon to display attachment inline comments (if there are unresolved inline comments in the attachments of that page).
Clicking on this will bring up a dialog where you can see a breakdown of how many unresolved inline comments are in each attachment, and clicking them will bring you to the attachment.
Then, clicking on the inline comment icon in the upper right corner will take you to the first unresolved inline comment, and you can navigate through all unresolved comments using the up and down arrows.
