Public folder in 2013 error

How to create a new public folder ?

I tried the GUI interface using the insructions here :

http://technet.microsoft.com/en-us/library/bb691104%28v=exchg.150%29.aspx

But i get error saying no active public folder (see screenshot), i have not used the shell.

I have created public folder mailbox already but when i go there and click on usage it says public folders user has not logged in yet ? What is that ? some user what would be its default password ?