Enter your Letterboxd username on the configure page, pick your catalogs, and click Install. Stremio opens and adds it automatically.
No. Without a password the addon is stateless — your preferences are encoded in the URL and you get watchlist, liked films, popular, Top 250, and any public list. With your password the addon runs in full mode: your config is stored server-side and you unlock diary, friends activity, and actions (rate, like, add to watchlist). Changing settings without a password requires reinstalling the addon.
Never. It's used once to get a session token. Only an encrypted token is kept.
Yes, on any platform that runs Stremio. Some actions may behave differently depending on the app.
No. You can install and use the addon without a Stremio account. A Stremio account is only required if you want your installed addons and watch history to sync across multiple devices.
It's in your Letterboxd profile URL: letterboxd.com/username.