I've changed them too - but again my Sportback has Xenon lighting. The process might still be the same though.
The sidelight sits with the driving lights nearest the radiator, and as I recall the wiring connector holding the driving light bulb comes out quite easily to leave a small aperture, inside which is another smaller connector for the sidelight. You'll find you can get several fingers into it, but not your whole hand.
The driver's side is easier to change because there's more room directly behind the headlamp unit. Peer inside the unit and you'll see the connector for the sidelight - it's the smaller one. I think it was coloured orange! Using a couple of fingers, get the best grip possible on the connector and twist it to remove. Pull the connector completely out of the unit to change the bulb - they just slot in. Make sure you test the new side lights at this point, because you won't want to have to take them out again!
The same applies to the passenger side but this time the airbox gets in the way, so there's much less room to get your hand into the aperture. Much of the time you work by feeling your way round the headlight - it's difficult to see what's going on!
Refitting is a bit tougher, because not only have you got to line up the sidelight bulb to go back inside, you got to push it home and twist it into the holder. I did this by visually checking where the bulb goes, then quickly standing up straight to get as much of my hand inside the headlamp as possible to put the bulb straight in. Otherwise you kind of get "lost" with the bulb not finding the hole!
It's difficult to describe exactly how to do it; but it took me all of five minutes. Yes it looks tricky because of the access but just get stuck in. You can't really break anything! If you're still REALLY stuck, and if I'm feeling particularly charitable this weekend (hey, it is Christmas), I'll go outside and take some pictures. Having done it before I could probably get the bulbs out quicker this time.