"Are you folks going to watch the championship game?"
Translation:E nānā ana anei ʻoukou i ka hoʻokūkū kahului?
In this scenario, we are starting the sentence with "E". This is because it isn't just "E", but instead "E... (verb) ana".
The sentence structure of "e... (verb) ana" basically means "will do (verb)". Basically, something you're planning to do in the future.
Since this question is really asking if they are planning to watch the game (in the future), we have to use "e (verb) ana". Hope this helps! Aloha.