I use 8 of the add-on sensors around the house. The sensors send back temp and humidity. If you add sensors, Ambient will automatically add the data to the json data stream as temp1f and humidity1 for the first sensor; temp2f, humidity2 for the 2nd sensor etc.... Here's how I added all 8 of my sensors:
Open the code for the "Ambient Weather Device" in your "Drivers Code" section of Hubitat
I've named my sensors after the locations that they're placed, but you can call yours whatever you want, but keep the names consistent between sections. I'm also showing you three sensors, but you'll probably need to add only one set, so you can just use one pair in each of the two sections.
In the "definition" section up top, add the following attributes:
attribute "watermains_temp", "number" //add-on sensor #1
attribute "watermains_humidity", "number" //add-on sensor #1
attribute "sump_pump_temp", "number" //add-on sensor #2
attribute "sump_pump_humidity", "number" //add-on sensor #2
attribute "attic_temp", "number" //add-on sensor #3
attribute "attic_humidity", "number" //add-on sensor #3
NEXT, in the "def setWeather" section of the driver code, add the paired "sendEvent" chunks of code:
sendEvent(name: "watermains_temp", value: weather.temp1f, unit: 'F', isStateChange: true);
sendEvent(name: "watermains_humidity", value: weather.humidity1, unit: '%', isStateChange: true);
sendEvent(name: "sump_pump_temp", value: weather.temp2f, unit: 'F', isStateChange: true);
sendEvent(name: "sump_pump_humidity", value: weather.humidity2, unit: '%', isStateChange: true);
sendEvent(name: "attic_temp", value: weather.temp3f, unit: 'F', isStateChange: true);
sendEvent(name: "attic_humidity", value: weather.humidity3, unit: '%', isStateChange: true);
You shouldn't need to change anything in the apps code.
If I recall, you need to open the "Ambient Weather Device" in the devices section, and hit "Refresh" but if that doesn't work, you may need to delete and then re-add the device. (I can't remember which...)
Don't know if all of that was clear or not, so let me know -- either way, Ambient should be feeding the data back to you in the data stream that it's providing....