Need Help

Hello
I am new with wordpress
i started my webpage with the piano-black theme and got to the nect problem.

When i creat an page i can choose between differet templates like no comment and no sidebar, but when i go to the main page i get a page were you see and can give comment.

My question is how can i change the main page to a template no comment, because the main page is the only page wich i can’t find out how to change to a page with no comment.