It's not too bad apart from the complete lack of room around there.
Slacken off the bolt through the adjuster bolt on the side of the PAS pump a little and then you can wind it up to loosen and help put on the new belt, snag is you will have to take off the alternator belt as well as the water/PAS belt is on the inner ring of the crank pulley.
Same thing with that slacken off the adjuster on the alternator a bit and wind it down to loosen (the opposite way to the PAS adjuster btw).
In typical Haynes manual stylee, fitting is just the reverse
You may have to move some plastic shielding from underneath the car to put the belt round the crank pulley if it still has it
Not a bad job really just fiddly. Prolly have to jack it up to get underneath but you may get away with that.
Apologies if this is in the PDF document, all I got was a blank page with this pants IE browser :?