If I make a page that is shown only those who are logged in, and I put files in those pages (that are in the subfolder of the assets folder), how do I make the content of the subfolder also shown only those who are logged in? Because now if I got it right, anyone can access those files if the right address is given (xxx/assets/subfolder/file.pdf)

And is it possible to create a member profile with only username and password. Now it requires email and password. I tested adding just a username to email field for one member and got logged in with that, but when I tried it in different browser it says either the email address or password isn't valid (so I guessed it requires the content in email field to be email address)

Hi, I'd look into .htaccess to do this or maybe the module http://silverstripe.org/secure-files/ might help

Is that username/password login method something what has been in SS before, but in later releases changed into email/password method? I found some old topics about member login with the usernames mentioned but there's no username field in the cms.

Ok, that helped me a lot! I needed a page to the site that can be accessed with only one shared username+password, which can be changed in the cms, so it's not a problem if someone forgets the password. I tried to use the First name field as the username, but of course it needed to be the email field to put the username.