dragon slayer 6 why "user disk"

hello ,I´M SPANISH AND I HAVE A PROBLEM WITH DRAGON SLAYER 6,WHEN START THE GAME IN THE FIRST MENU A MESSAGE SAY "PLEASE INSERT A USER DISK AND PRES ENTER ",WHAT USER DISK!!!!!????I DONT KNOW

If you play it for the first time, you have to watch the complete intro demo. After that the game will begin and you can save the game to an empty disk.

If you have an userdisk, you can press space during the intro demo and it will ask for the userdisk.

thank you very much, uff my english is 0.... sorry