Update offline.md (mdn#5651)

* Update offline.md

* prettier

Co-authored-by: Florian Merz <me@fiji-flo.de>

copy/plus/features/offline.md

@@ -5,9 +5,48 @@ title: MDN Offline
 # MDN Offline
 
 > Web docs without web access: the full power of MDN, offline
->
-> Leverage the offline capability of our MDN PWA to work on the go. Whether you're in a high-speed train, a cabin in the woods or just looking to save some data, MDN Offline gives you access to the full power of your favorite dev resource, so your projects aren't interrupted. The site is snappier and your experience better.
 
-When you need access to MDN even without an internet connection, MDN Offline allows you to browse the most up to date version of the site, or simply to have a faster experience while saving data.
+> Leverage the offline capability of our **MDN PWA** to work on the go. Whether you're in a high-speed train, a cabin in the woods or just looking to save some data, MDN Offline gives you access to the full power of your favorite dev resource, so your projects aren't interrupted. The site is snappier and your experience better.
+
+When you need access to MDN even without an internet connection, **MDN Offline** allows you to browse the most up to date version of the site, or simply to have a faster experience while saving data.
 
 ## Getting started
+
+To start using MDN Offline, you must first **Enable offline storage**.
+
+1. Click on your profile photo and open the **user menu -> offline settings**
+2. **Enable offline storage**
+
+> **You can also add it to your homescreen for an experience similar to using a native app**.
+
+## Choose how to stay up-to-date
+
+1. Enable offline storage
+2. Choose how to update
+3. Manually update by clicking **Update now** or **Enable auto-update**
+4. Clicking **Update now** will start the download of the latest version of MDN Web Docs.
+5. The date of the last update you will shown.
+
+## Clear stored data
+
+Open the user menu -> offline settings
+Clear data
+
+## Supported Features
+
+Some insight into what can be expected from using MDN offline
+
+### Browsing Content
+
+If offline mode is enabled, offline content is preferred. All content works without an internet connection, with the exception of a few github-based examples and large video files.
+You can also indicate you prefer offline content even when online.
+
+### Collections
+
+Previously saved pages will appear as such, and you will be able to browse your **Collections**.
+However, editing a saved page (adding/removing) does not work without an active internet connection.
+
+### Notifications
+
+Previously received notifications will be displayed and can be read.
+However, notifications read while in offline mode will not be marked as read for later, and cannot be starred or deleted without an active internet connection.