Doubts about STL libraries

[tonnot]

I'm learning c++ and I have a great confusion about standar libraries.

Why QT creator does not provide help about it ? (It is not neccesary to answer to this...)

I dont understand why I must to use std::----- . What is std ? is there more 'workspaces' ( I dont know how to name it) ?

I have found a good reference here, http://www.cplusplus.com/reference/string/, anybody knows other ? A way to get help for inline help into QT Creator ?

Thanks
Moved to general