All you have to do is put a little soap and water inside the brush and put your fingers inside. Move the brush like you would for any normal brush, and it gently scrubs your fingers. I found the Bruzz a bit too harsh even though it claims to be gentle, maybe it's because I have short fingernails! I can imagine it would work better for girls who have really long fingernails or rectangle-shaped ones, rather than my short stubby nails. I also didn't like the vanilla scent of the brush, it smells strange. However, that's just me being picky because I just don't like artificial smells!
What I really like about it, however is the fact that it is really easy to clean. The brush bristles are detachable, which makes it easy to clean and wash. I had no trouble cleaning it after my nail cleaning session. And I bet it works for toenails too so I'll definitely be trying it as my toenails are dirty (lets not go into that!)
Before cleaning with Bruzz- just your average dirty nails with bits of brown in them!
After cleaning with Bruzz- more cleaner, whiter nails
Overall, I'd recommend the Bruzz if you have really long nails and would like to clean them easily. The Bruzz's quality is very good and the brush is well-made and sturdy. It also gave me a good effect with the nail gunk. The Bruzz costs £9.99, but some shops sell them slightly cheaper.
The official BruzZ website has more information and details, and also has an online shop.