There is no specific PWM pin mapping for the nRF52833 DK. All nRF5 series ICs has a pin crossbare feature that allows you to connect any digital peripheral (UART/SPI/TWI/PWM/I2S/PDM/etc.) to any GPIO.
The pins are configured by setting the PSEL.OUT[n] register in the PWM peripheral, or through the PWM drivers.
