Frequency Programing

[VK5GRR]

I own a Icom 2730 A and was wandering how-to use it on both Frequencies UHF and VHF. on Uhf when i push PTT button the unit reads OFF on the screen ?.
I can receive On UHF and VHF but cant Transmit on UHF. Is this My settings are Wrong or is it the Radio
Your suggestions would help
Cheers Glenn VK5GRR