First you will need to download the student Quizizz app here.
The students will then need to enter in their quiz code and then select the three lines (upper left corner). There the students will see settings. The third one down is the read aloud option.
Once this option is toggled on - when the student would like the question read aloud they would need to simply select the icon that looks like a student (upper left).
Embedded below is a 1 minute and 21 second YouTube tutorial.