The sample code above will not work properly until you’ve correctly changed the channel number for each of the 6 sensors. Also, once you do that and you have a different number of sensors other than 6, you’ll need to change the number in line 31 to the correct number of sensors.
So first you should make sure you change the channel number of one sensor at a time and then verify that the sample code for reading one sensor works properly before proceeding further.
To connect a Decagon 5TM probe to your Arduino board, connect the sensor bare braided wire to a ground pin of the Arduino. Connect the white sensor wire to 5V, and connect the red sensor wire to the data pin (pin D7 in the example above).