Add supported features to Bang & Olufsen

source/_integrations/bang_olufsen.markdown

@@ -53,6 +53,16 @@ Device model:
 
 The **Bang & Olufsen** integration uses the [Mozart API](https://bang-olufsen.github.io/mozart-open-api), which is a local REST API with a WebSocket notification channel for immediate state information for media metadata, playback progress, volume etc. The only exception to this is the repeat and shuffle controls which are polled every 30 seconds.
 
+## Supported features
+
+Currently, a single device with a `media_player` entity is created for each added physical device. For advanced automations, [events](#automations) are fired in Home Assistant.
+
+### Media player
+
+The media player entity enables users to see and control media curently being played on their Bang & Olufsen device. Additionally, users can play media through [play_media actions](#play_media-actions), select active sound mode, switch between sources and control repeat / shuffle settings.
+
+[Beolink](https://support.bang-olufsen.com/hc/en-us/articles/4411572883089-What-is-Beolink-Multiroom) is available to all Mozart devices that have been added to Home Assistant through `media_player` actions. For more advanced usage, such as connecting [ASE](https://support.bang-olufsen.com/hc/en-us/articles/24766979863441-Which-platform-is-my-Connected-Audio-product-based-on) products not available in Home Assistant or expanding sessions to all discovered devices, [custom Beolink services](#custom-actions) have been defined, with current [Beolink state](#beolink) available in media player properties.
+
 ## Actions
 
 ### play_media actions