You can first try to replace the batteries in your remote. If that doesn't solve the issue, reboot your entire system by disconnecting it from the disconnect switch for at least 30 minutes.
If you still can't get your unit to power on, you can try to power on your indoor unit manually by pushing the auto/cool button twice, which is located underneath your front panel on the bottom right. If you can hear a beep or notice a 76F on the unit, your remote control must be replaced.
If your system still won't power on, you can refer to the attached PDF on how to diagnose the issue with your system.