Yes. Please read the readme.txt file included in the download (in Wolf's root folder). There is also an installation manual on this wiki.
Assuming you have used the correct username and password (given to you at the end of the install screen), the problem might be with your PHP session.
Check the end user documentation on the wiki.
To restrict viewing privileges for certain pages to users logged in to the backend.
To do this:
Consult the Create a Sitemap “howto”.
Strictly speaking: yes. (please read the note below!)
However, we ask you to show your support for the Wolf CMS project by keeping intact the “Wolf CMS Inside” line in the footer.
Important - Concerning copyrights.
It is not allowed under any circumstances to remove and/or change the copyright notices in the files that make up the Wolf content management system.