Using this BIOS DT131 digital thermometer is a breeze. First, make sure the battery is installed. Then, insert the 3 - inch probe into the item whose temperature you want to measure. Wait for about 5 seconds, and you'll get an accurate reading that updates every 2 seconds. You can use the min/max memory function to see the highest and lowest temperatures recorded. As for maintenance, since it's waterproof, you can gently clean it with a damp cloth. However, don't submerge it for a long time. Keep it in a cool, dry place when not in use. If you need to calibrate it, follow the simple calibration steps in the user manual. And always check the battery level regularly to ensure it works properly.