like nearly all websites we store your preferences in a small file (cookie) in the browser on your pc. on a subsequent visit, you do not have to set your preferences again.
the cookie law requires us to ask you permission for the posting of this file.
after setting your preferences, you can click on "save your changes" , giving us permission to store a cookie.
if you click on "do not want that" you go back to the starting page without storing your preferences for the next visit.