On the game show Jeopardy for the final question how do you determine your wager?.?

I mean do you bet before the question is asked and wager solely on the topic of the question or do you wager after you write down your answer and wager on the fact that you know or do not know the answer?On the game show Jeopardy for the final question how do you determine your wager?.?
Wagers are made after you see the category, but before you see the question.