They done a good job explaining it. I've had these pics hosted for a while, I posted them somewhere else, but here you go.
These first two I have my forearm up just slightly, but you still get the picture.
Aligning the disc in the life line, and just under the very first index knuckle will put the disc where it needs to be, as shown above.
As you can see, this last picture the disc is more neutral. The wrist is the same, the disc is below the life line in the hand. So, it makes it even harder to establish nose down, this is why it's important to keep the disc under the first index knuckle, and in the life line area of the hand to maintain good nose down.
Also, I stress that you maintain the maximum amount of nose down until you absolutely are able to manipulate it. As EVERYONE loses a small amount of nose down due to the wrist straightening, this is natural and will always happen due to grip strength. But, if you know how to power through wrist extension you can gain it back, but that's another story. But, this is why I stress maintaining as much nose down as you can, because you'll always lose some due to grip strength issues when the wrist opens to neutral. I know this is late, but I just got around to posting it.
*Edit* I"m still working on trying to get video of some long distance putter throws as I haven't been able to acquire a camera. As soon as I can get that, I'll post it up for you all to see.