Asav, I assume by ‘citro specialist’ you mean Citroen parts dept at the official Citroen dealer, The price is right, but to be sure does the bottle look like this?
As for the plug tool Citroen themselves won’t have that, you need a car parts & tools shop, like Halfords or an independent.
The first two pictures are to close to the front of the car, the 3rd picture is the one you’re after, as you can see the bolt/plug is slightly obscured by the gear selector arm, which I think your refereeing to as the ‘clutch cable’, there’s no clutch on an auto

. The obstruction of the gear selector arm is why you need to put the car in 2nd to get decent access to the drain bolt. If you can clean up the area around the bolt before removing to ensure no rust falls into the box, spray carb cleaner or clutch cleaner I find useful, that and cotton rags (use some old clothes).
You also want to buy one of these, it’s a funnel with a flexi tube and a mesh filter built in, the blue part is also an on off switch. I have one of these, found it most helpful, sadly I bought from a local independent and can’t remember brand name nor part name.
.i really am a total new boy when it comes to cars
Don’t worry we all start somewhere.
but i like trying to learn new stuff and do it for myself...if possible
That’s the spirit, don’t worry if you make mistakes a few times, there’s always a learning curve, just be patient and take things slow, take time to think, remember to eat and drink, if your tired take a break and go back to it later, the amount of things I've broken by trying the job when I'm to tyred.
Gone to the dark side.
Past Citroens
'99 Xantia HDi Exclusive
'99 Xantia 3.0 V6 Exclusive (Green Goblin)
'02 C5 Hdi 110 LX Estate
'98 Xantia 1.8 sx auto with LPG
'00 Xantia Hdi (110) forte
'97 Xantia 1.9D sx
'93 Xantia 1.9D lx (my first) R.I.P