Update README

README.md

@@ -5,26 +5,26 @@ badge with the number of unread articles.
 
 ## Setup
 
-1. Install the extension: [Firefox Add-Ons](https://addons.mozilla.org/addon/freshrss-checker/)
-   - [Chrome Web Store](https://chrome.google.com/webstore/detail/freshrss-checker/fkckemcdpfnblnkndachclpjfmlhofeg)
-2. Open the extension's preferences page from add-ons manager and set the FreshRSS base URL, username, and API
-   password (not your regular password, remember to enable mobile API access).
-3. Place the toolbar icon in a visible location if you want to see the number of unread items.
+1. Install the extension from [Firefox Add-Ons](https://addons.mozilla.org/addon/freshrss-checker/) or
+   the [Chrome Web Store](https://chrome.google.com/webstore/detail/freshrss-checker/fkckemcdpfnblnkndachclpjfmlhofeg)
+2. Click the extension icon and set the FreshRSS base URL, username, and API
+   password (**not your regular password**, remember to enable mobile API access).
 
 ## Build
 
 1. Clone
 2. Install dependencies with `npm ci`
 3. Run `npm run dev` for bundling the JS
-4. Run `npm run start:chrome` for starting the browser with the extension pre-loaded and ready for debugging with
+4. Run `npm run start:firefox` or `npm run start:chrome` for starting the browser with the extension pre-loaded and
+   ready for debugging with
    hot-reloading
-5. Build with `npm run build`
-
-Primary development target is Chrome.
+5. Build for production with `npm run web-ext:build`
 
 ## Usage notes
 
 - Clicking the toolbar icon opens your FreshRSS instance
+- Firefox users can open FreshRSS in the sidebar instead and default to it, which will also change the context menu on
+  the icon accordingly
 - Right-clicking it and choosing "Check now" forces the badge to update
 - The time between checks can be set in the preferences.
 - The password is stored in the extension's local storage, effectively in clear text on the file system. It's not