They are autobrakes . Use them on landing on either 1, 2 or 3. Setting one is used for normal conditions, i.e. dry and clear, setting 2 is used if the runway is wet, 3 or MAX are normally used in cases of emergencies. 1 is standard though. When you land, it will brake automatically for you so you don't have to. RTO means rejected take off and is used on take off if there is a fault and the take off is rejected, the plane will stop using these brakes. They are of the same power as the MAX setting. Hope that helps 😀
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