A really simple way to get to know Goldie would be to try placing things of different temperature on the flat plate of Warming Base - like a jar of warm water or ice water - you will see the Temperature Lamp change its color.
To test Goldie’s warming performance, you can take the temperature of your starter using a probe thermometer (like the one you’d stick into dough or a piece of meat). Make sure your starter has a chance to warm up before testing the temperature. If your starter was in the fridge, or if your home is on the cold side, this may take longer.
Another way to test Goldie is to use infrared / laser thermometers. Point the laser at various points on the warming plate while the auto-warming is turned on. If you read a range between 75-82ºF / 24.4-27.7ºC, your Goldie is in business!