Assuming you really are starting from zero—
First read this excellent article.
It is the best step-by-step guide I’ve seen to getting OpenHab working on Pi. Even includes specifics on configuring a Hue setup.
Details on the Hue binding are here:
Get the Hue running first BEFORE you attempt the Plex or Sonos. It is more straightforward device and the examples in the MakeUseOf article and Hue binding doc are more complete.
You’ll also need to install the Plex and Sonos bindings and configure them.
Plex details at Plex Binding · openhab/openhab1-addons Wiki · GitHub
Sonos details at Sonos Binding · openhab/openhab1-addons Wiki · GitHub
Sonos binding doc suggests that there were/are problems with a buggy UPnP library.
Rule of thumb for your ITEMS:
Things that you are not controlling but merely displaying are Number or String, as in this from Sonos:
String currenttrack “CurrentTrack [%s]” (Sonos) {sonos=“[RINCON_000E581369DC01400:currenttrack]”, autoupdate=“false”}
Things which you are going to control and have simple on/off points are Switches, as in:
Switch PlayLivingRoom “Play/Pause” (Sonos) {sonos=“[ON:living:play],[OFF:living:pause]”}
Things which you are controlling that have a ranges of values (dimmers or volume for example)
are usually Dimmers in your ITEMS file but Slider in the sitemap. Again from Hue,
(from ITEMS)
Dimmer Dimm_1 “left bulb” (WhiteDimmer) {hue=“1;brightness;30”}
(from Sitemap)
Slider item=Dimm_1 visibility=[Toggle_1==ON] label=“Bedroom Brightness”
(EVENTUALLY - you will also need to eventually stop using the Pi’s SD card except for booting and use a USB stick or USB-attached disk. See this thread re that topic.
The link @watou posted at the end of the thread is good. I wish I’d had that rather than having to hand-roll via the links I posted in same thread).
Hope this helps.