别的... is an adjective.
It means other.... This word is always followed by some nouns.
For example, 别的事情（other things），别的人（other people）
主要 means mostly/main. it is a little bit similar with important.
For example, 主要内容（main point），主要目标（main objective/goal）
Now our main goal is to beat the opponent, everything else is/other things are not important.
Cici, I hope this will help you.
Actually, you can explain your questions in more details. I think it is easier to understand new words by using them in sentences, instead of just studying the words.