The heart of the matter right there. At the bare minimum, you need a dedicated student cheering section willing to partner with the cheerleaders and learn the basic cheers. And the cheering team coach needs to buy in also. If you encourage it, they will come.
Back when dinosaurs walked the earth, we had things called "pep rallies", even on school time. Each new freshman class learned the cheers at these events by following the upper classman. We looked forward to the brief respite, and we participated heartily. We knew that if we didn't, the principal would've stopped having them.