Lots of folks have had issues with this as the low beams aren't readily accessible from under the hood. I read some of the posts about taking off the bumper, etc. and decided to follow what's in the manual first, then would pull the bumper if I had to, but was pleasantly surprised - I think I know where folks who have had troubles have gone wrong.
First, for the first time you try, I would lift the front of the car and take off the front wheels - probably not necessary, but it gives you space.
Next - pull the pop-its from the fenderliner - pull the three along the bottom that hold it to the bumper, then undo the two little ones that hold it to the undercover, then undo the large one inside the wheel well and one on the front inner surface of the wheel well liner (I marked the ones to remove on the figure)
Now pull the fenderliner out from under the fender, and fold it inwards out of the way (easiest to do if you grab and the front and sort of slide it backwards - there are two metal "hooks" on the edge of the fender you need to lift it up and over) - you don't want to be shy here - make sure it's out of the way (it might not stay there, so you'll need to hold it when you are in there)
You'll now have a clear view of the back of the headlights - you want to be reaching straight back, rather than from down below - I think that's where folks go wrong - not pulling the mudguard back enough, then reaching up from below to get to the headlight.
Unscrew the dust cover over the bulb (it only turns about an eighth of a turn) - now you can clearly see the bulb.
Remove the connector (it pulls straight off)
Remove the metal clip (the clip releases from the left side - you push the end down a bit and it releases from the latch)
Pull out the headlight bulb - now look at the back of the headlight at where the bulb goes - the bulb only goes in one way - note where the key is, so that you can put the bulb back in properly.
Insert the new bulb (make sure you don't catch the clip) - it should seat flush with the light housing and not rock around. Once you are confident it's flush, pull the clip back over it (push it down to engage it on the hook) then look to make sure it's seated properly
Plug in the harness
replace the dust cover
put the fenderliner back
Done! now do the next side.
Took me about 10 minutes per side, and I was taking my time - as with almost all repairs, having the room to work is key in getting this done easily. First time out, give yourself as much room as you can - once you know what you need to do, you can try working with less room. I think you could do it without removing the wheels (just turning them) so maybe next time, I'll do it that way.