A zone has a state which is a number corresponding to the number of tracked devices in it. This would be the trigger for your automation - no need for any conditions.
Just a slight correction to Jack’s description… The state of the zone reflects the numbers of person entities in the zone, device trackers themselves aren’t part of the count.
When you’re testing, bear in mind that the number of person entities in the home zone has to change from zero to above zero. If it’s already above zero when you start testing, nothing will happen.