I have a home furnace with a lennox control. It's about 30 years old.

The problem is that, when the room temperature is cold, like 55
degrees F, and the control is set to 70 degrees F, the furnace only
runs for about a minute, shuts off for maybe 3 to 6 minutes, then runs
for another 1 minute. I'd rather the furnace ran until the temperature
reached 70, then turned off and turned on again when the temperature
dropped to, say 67.

There seems to be a way of setting things when I take the cover off
the control. But how do I use it? Is it possible to get the controller
to work as I like?