When you locate relay T01 at bottom centre of the cab fuse panel, try switching on the ignition and then the dipped beams. You should hear the relay click. It may also help to hold a finger tip on the relay. If the relay clicks, remove the relay which may be tight in the socket.
With the relay removed the two smaller sockets are the coil terminals. If you are satisfied that the relay has been clicking proceed to the next step.
The large socket furthest from the smaller coil sockets is terminal 30, and is traditionally connected to 12V. Treat with respect, and avoid shorting to chassis (earth). Bridging the two larger sockets together should illuminate the dipped beams. TAKE CARE.
If relay has not been clicking, with ignition on, check the two smaller terminals for 0V and +12V with a multimeter, connected to either battery positive, or battery negative as appopriate.