Java around the world

Ok I downloaded the Public Test Realm server thing ok i got on i understand you have to download stuff well i downloaded the one that I have on a regular Realm but i want to know how can I download the premade when it says i cant i never downloaded premade. But on another account that I had I was on the Pubic test thing and i could download the premade why cant I download the premades on that account please help me I really want one thanks soo much!