How to Change radio frequency on universal music decice

I’ve reset the device to try and find a way to change the frequency and it went to 100.0 which is impossible to tune a radio to. So there must be a way to change it on the device but I can’t figure it out and there’s nothing online that I can find.

I have 2 of these devices. To change the frequency of the transmitter, press the up or down arrow until the number flashes. Press and hold to change the frequency fast, single steps by short press. If you are using the aux input then the transmitter will not need to be changed.