Hi Darren - and Welcome
It's great that you have joined us!
The platform you refer to is a really clever bit of design, albeit a bit out of date now that shell doors on recent ships convert to a landing-stage / pontoon, without needing a stairway.
When it's not possible for the ship to be tied up alongside, as Louis mentions - the platform is hoisted off from above QE2's Boat Deck - then after being secured on the side of the hull at sea level, it's used by crew and for pax to join launches that take people ashore.
(It wasn't till quite recently that during a conversation re tendering, realisation dawned as to just how precarious these manoeuvres can be...no-one in charge seems to like it that much! Easy to see why, pax who are unsteady on their feet can have an extra tricky time in long swells...)
IMG_4900 This next image doesn't do the transferring business justice, however it shows the steps - will find / add more when time's less scarce!
(Although - Yes, I know... time's infinite too!)
https://www.flickr.com/photos/watch_keeper/3468508022/More here:
https://www.theqe2story.com/forum/index.php/topic,429.msg43487.html#msg43487This is how it's done on QM2, no external steps, and a hatch door/pontoon that can be swiftly secured.
https://www.flickr.com/photos/49847205@N00/4210913371/