The way this works is by right-clicking on a link and then selecting PTW Extender's context menu.

[Features]

Allows you to add titles to your MyAnimeList, AniList, or Kitsu plan-to-watch list with the url of where you found it added as a comment.

Allows you to modify settings such as whether a title is private or public, whether it's available to all viewers or only for logged-in users, whether it's a plan-to-watch list or a plan-to-read list, etc.

Allows you to save settings so that you don't have to change the settings every time you start a new browser.

Allows you to submit updates, which will be reviewed, approved, and added to the PTW list.

Allows you to cancel updates.