I can’t find the resivour I don’t know how to access it
From page 43 of the manual, available online:
On Chevrolet chassis, the master cylinder is located under the driver's compartment floor, and is reached through the left front wheel well. On John Deere chassis the master cylinder is located near the left front of the transmission
Fill the master cylinder with a squeeze bulb or pump. Check and fill the master cylinder according to instructions in the chassis operator's manual.