If you're going to be working with a Qlik product you're going to have to dive into Set Analysis. There is a wizard you can use here. But you're going to want to avail yourself of a lot of googling if your company won't send you to training. If you aren't working for a company you will want to consider paying for yourself to get training.
Googling "qlik sense max by dimension" yields this link which will explain how to do this - it's the same for QV or QS.
If this answers your question please remember to mark it as the solution.
