How do I repressurise my glow-worm 30cxi boiler?

Hi, I'll apologise straight off for being RUBBISH at DIY. My boiler stopped working today, the wee display is flashing 0.6bar and the red alert light is also flashing. According to the sticker on the front it needs to be at 1bar to work. I have not the faintest idea how to repressurise it! Can someone please explain it to me (preferably in small, easy to understand words - drawings also help!)
Thanks!