In Configuration_adv.h
eg
#if ENABLED(THERMAL_PROTECTION_HOTENDS)
#define THERMAL_PROTECTION_PERIOD 40 // Seconds
#define THERMAL_PROTECTION_HYSTERESIS 4 // Degrees Celsius
#define WATCH_TEMP_PERIOD 20 // Seconds
#define WATCH_TEMP_INCREASE 2 // Degrees Celsius
and for the bed
#define THERMAL_PROTECTION_BED_PERIOD 20 // Seconds
#define THERMAL_PROTECTION_BED_HYSTERESIS 2 // Degrees Celsius
#define WATCH_BED_TEMP_PERIOD 60 // Seconds
#define WATCH_BED_TEMP_INCREASE 2 // Degrees Celsius