That guide is for a specific cup holder sold on ebay, and fitted to M49/M59 Berlingos.
It requires a free DIN slot(typical stereo size without the big screen. Those are Double DIN) and an 'DIN Stereo Cage' used to anchor those stereos.
Remove the cubby in the empty slot, slide the ISO cage in, bend tabs to secure it in place, slide the cup holder into cage.
The holder is still sold, but as it's mostly Chinese sellers pretending to be in England, many of them are listed as 'Double DIN' size' They're also not very good if you have a tall cup. Mine is very tall, and holds 450ml. (Got to have my tea in the morning) In fact, that broke the spring of the 'tensioner' that's supposed to hold the cup steady.
500ml Energy drinks will also cause the same problems.
For B9 or K9 models(from 2008 to the present) odds are that that won't work.
(They have a single 'Double DIN' slot for the stereo/GPS/backup camera/whatever beastie with a big screen that's fitted.
Here's the cup holder I'm using in my 2014;
It just slips into the crack between the two passenger seats of my Van.
(Cost me about £5 at the local parts blaggard. Sorry, it's BILTEMA, so maybe take a trip up to the Nordic countries to get one)