Honda FourTrax Rancher TRX420TM1 2020 Owner's Manual page 52

Controls & Features
To release the parking brake:
Squeeze the rear brake lever/parking brake lever until the P/R lever is
released from the slot on the rear brake lever/parking brake lever
bracket.
The brake light is activated by applying the brake. When using the
parking brake, be sure to turn the ignition switch to OFF (w) to avoid
discharging the battery.
To shift the transmission into reverse:
For information on Riding in Reverse, see page 81.
42 Instruments & Controls