Do you have one of these grinders? It looks like the basic model I have played with but differewnt outside plastic but alas, I have not played with this specific model.
Does the upper burr just unscrew out of the housing (back it off until it comes out??)?
What I have found on most grinders is a plastic tab that hits when the burr is turned into a certain point. I usually grind that tab off and then it can turn in further. Beware, this will allow the burrs to touch when turned in too far OR lock up the grinder altogether if turned in all the way then turned on. I know I know, stupid stuff but in today's day and age, you have to say the stupid stuff or people get mad.
If you want, unscrew the top section (hopper, upper burr) and take pictures and send them too me and I will try to point out what needs to be done.
Once again, I have not played with this particular grinder but I have found they all are pretty similar.
Scott