No communication

Hii i Have several questions about the cube orange and I’m using herelink 2.4Ghz:
1.what does the plane do if i lost communication?
2.what will happen if i lost Gps?
3.And what will happen if i lost both?
And What is fcc mode

May I know what firmware did you use?

There are some fail safe option which you can set it for different condition.

FCC(Federal Communications Commission)mode is a radio transmitter power mode.

How do i operate fcc?
Im using QGROUNDCONTROL can u explain to me how should i set those fail safe and what are the optionsFor no communication and no Gps?
How do i change fcc mode

Do you use PX4 or APM ? (firmware on your cube orange)
This the doc for gps-failsafe and other failsafe.
https://ardupilot.org/copter/docs/gps-failsafe-glitch-protection.html
https://ardupilot.org/copter/docs/failsafe-landing-page.html
You can use QGC on your controller to set relative parameter .