I am having a report where first I have 2 dimensions and then one measure.

 I want to sort the report based on the sum of the measure corresponding to the 1st dimension. But when I do it sort based on 2nd dimension

Let’s say we have the report like below-

And you want to sort these on the basis of category and not segment then simply click on category icon and select sort. There select field and then the field on which we want to sort it.