The phase (or positive if DC) is applied on 5.
Depending on the voltage the neutral (or negative if DC) is applied on 1,2,6 or 7 (2 for 24V) you apply on only the relevant one. The voltage depends on your heater or cooler.
3 and 4 are outputs will be internally connected to the phase depending on the temperature. you connect the heater to 3 or the cooler to 4.