[Koha] dewey class and subclass etc

[Eric G. Salayon]

can anyone explain how should i fill up information in adding a new item?
like the Dewey, Dewey sub class what is this? When we tried, we keyed in
'005' and '133' accordingly but when c searched for the said book what we
saw on the Dewey info was 5.133, why? what does the 'Number' indicate?
another is the grouping, what is this for? i havent seen a entry for the
said grouping..
How can u edit the data that you entered? im confused while finding a way
to do this. and also after searching for items, does the system display
the call card no, author no etc? pls help!