Each student is assigned a unique Plickers card when created on the “Classes” page. To change a student’s card, just drag-and-drop one of the available cards onto the student.
Right now Plickers supports up to 63 students. If you have more than 63 students please Let us know. Currently, the way teachers handle larger classes is creating two Plickers classes for their single class, assigning their questions to both classes, and scanning the students in waves. You can distinguish the two sets of students by their location (front class goes first) or using colored paper or stickers to determine which half of the class the students are in.