check out user manual for UDT, which has been updated for the latest versions accordingly, thanks to team member Brett Conlan. I know, that other teams (Documents, Gallery, ...) are working on documentations as well, but this is a time consuming task and there will always be at least a time gap. There are other teams, which has more difficulties providing proper manuals, especially the one man shows, and not all developers are good in writing. So, if you want to contribute a documentation, please contact the team lead and offer your help, most of us will be glad

My experience setting up my first DNN site was bad and a large part of that was because of poor Skinning documentation.  I can't believe DNN hasn't updated this yet considering how important it is.  It's a monumental failure IMHO.

The reason i think it's so important is that's where you get user buy-in.  If you want to get people using DNN (so you can sell stuff to them) make it easy to get it looking the way they want.  Many people aren't going to use much more than the HTML and Forum modules, but every one of them will want to customize the look.  If they can't do that easily, they'll quickly move on to something else.  I very nearly did.

I don't think it's needs to be so "hands on", either.  You could probably trim down most of the skinning guide to 3-4 pages of general information, and then list all the Tokens/Controls with a very brief description/syntax.  That way you only need to update the Token/Control list.  Developers will keep lists updated.  It's when you make them write paragraphs they find other things to do.

Where can I buy  (book or pdf or online) correct information of how nav skinobject works??

By the way online help are never accurate :)