I think your timer is technically a water heater timer, not sure that really matters. As above, from the heater wires, connect red to +ve, brown to -ve and one side of pump, green / red to other side of pump . Putting yellow to +ve should start the pump pulsing and the heater going. You'll need a decent battery, as it'll pull a lot of amps on start up. The green/ red wire will only start giving out a pulse when the heater tries to start.
