I just added an option for “contact-garage” to my GoControl/Linear Multifunction Contact Sensor device handler so if you switch to that one you won’t have to modify the code.
If you’d prefer to keep the the simple version of the DTH and modify the code, all you have to do is replace “st.contact.contact.closed” with “st.doors.garage.garage-closed” and replace “st.contact.contact.open” with “st.doors.garage.garage-open”.