Arcing faults can be caused by damaged, or improperly installed wiring. These faults can get very hot, and are a common source of house fires. Driving a nail or screw into a wire, rodents, loose wire nuts,or even age can cause a wire to fail.
These breakers will not reset, until the fault goes away, or the wire is repaired.
If it keeps tripping, call a qualified electrician to locate the problem.
You can test an Arc Fault breaker by hitting the button. It should pop open the breaker. Then you turn it all the way off, and then back on again.
If you find an Arc fault breaker that is tripped in your house, first unplug everything om that circuit, then try to reset it. If it resets, then it could be a faulty cord or device that is plugged into it. If it still trips then call an electrician, because you may have a serious problem.