Go to one of the vid links. Click the large "Connect to Download Server" button. This one is tough to find for Germans.
Click on the linked "hier" above the two login screens.
First dialog box is your desired username. Next two are double entries of a password, next two are double entries of a real e-mail address (you need a real one.)
You can select your timezone, etc etc, not too necessary since I know you really want to see the vids.
Uncheck the last two checkboxes unless want to get nice e-mails in German.
You should receive an e-mail in less than a second. Click on the first link (Um deine Registrierung abzuschließen, klicke bitte auf folgenden Link: ), which should bring you to a new page which looks suspiciously like a welcome screen, because it is.
Close all that, go back to the original place where you clicked on "Click here to connect to download server." Click that, login with your username and password, and watch movies away.