Since the side of the laptop that the keyboard is on acts as the motherboard base and also due to the sleek look of the laptop, complete disassembly of the laptop is required to access and remove the keyboard - this video gets you about half way there and seems to be the most complete tear down info for your laptop
https://www.youtube.com/watch?v=YatNrUHN3c4 - I'll suggest taking a lot of pictures during the rest of the disassembly process to help with reassembly
Because of the design, I will suggest (it will be easier) carefully prying off the spacebar key cap and cleaning underneath it this video may help some with that
https://youtu.be/qXP1_WjtBP0?t=3m7s