Try setting up your incubator like if you were gonna use it.
Put some egg boxes (preferably all of them) in the incubator put the t-stat prob in one of the box (preferably the one located in the middle of the incubator, and place a thermometer at the top, and one at the bottom (put the probes inside the egg boxes)
Just remember those thermometer are not that accurate, I have found that they are about 2 degrees off, however it gives you an idea on your temps.
Here is how my incubator was setup for the first test run(no eggs just egg boxes)
Hope this helps.