I just bought a Noma Programmable Thermostat from Canadian Tire. My original thermostat was called a York and it is old with mercury capsules inside.

The original wiring is as follows:
Green to G
Yellow to Y
Orange to O
Brown to B
White to W
Red to R
Beige to X

Note that the new thermostat can handle a humidifier but our furnace does not have a humidifier so this functionality will not be used.

The new Noma Programmable Thermostat has only the following wire designations:
W
RH
RC
Y
H1
H2
C (has no screw)
G

I assume that:
white will go to W
yellow will go to Y
green will go to G
but how do the other wires go?

Many thanks for your help.

What is the thermostat controlling? If it is just a furnace (no a/c, no humidifier), then you should only need White and red to W and RH. You can also check on the furnace side of the wire to see what everything is connected to there

The furnace is used for heat, AC, and when below -15C a heat pump kicks in.
Thanks!