I usually like to sort them based on how I would want them to be in the Step 2 portion, then returning to Step 1 and selecting "Step 2 Order" in the Box Sort.
Maybe? I only use desktop for creating quizzes, but I went to mobile version on desktop and I can find the Box Sort by clicking the gear at the top right. I don't know if it's available in mobile but I assume so.
boom, the order you want your buttons to be