Lost with the rules of the challenges

Submitted to Community Café

Hello Community, I am new here and a bit lost. How does the voting work for those challenges? Do people really vote others down? And do they vote for themselves? When the most know each other, has a newbie a chance to get some votes? Do you vote every day again? I am just unsure if I understand the way it should be done :-( please give a clueless person a hint :-D thnak you!