Summarize the following:
This will ensure you get the best results. Check that the egg is not cracked or misshapen. If the egg is dirty, use room temperature water to carefully wash off the dirt on the egg.  If you find the egg, try to guess how long since it has been laid. If it is warm to the touch, it may have been laid within one to three days. Make sure the egg is at room temperature before you put it in the incubator. An egg that has been kept in the fridge will need to be left out to warm up before it goes in the incubator. You may mark the top of the egg with an “x” and the bottom of the egg (the small end) with an “o.” This way, when you turn the egg, you can keep track of how often it is turned. Close the doors of the incubator once the egg is inside. This will keep the humidity inside the incubator. It takes around 26 to 29 days total for Mallard duck eggs to hatch. From day 1 to day 25, the temperature in the incubator should be 99.5 degrees Fahrenheit (37.5 degrees Celsius). The relative humidity should be 86 degrees Fahrenheit (55%). On the first day of incubation, check the incubator regularly to ensure it is at the right temperature and humidity. The first few days are crucial for proper incubation. Turning the eggs is a key step in the incubation process. Use your hand to turn the egg so it is on a different side. Then, wait a few hours and turn the egg so it is on its other side. Do this three to seven times a day to keep the eggs at the right temperature.  The more often you turn the egg, the better it will hatch. Get into the habit of turning it an odd number of times each day for the 25 days of incubation. You may write down the times you turn the egg in a log for reference. Do not leave the eggs in the same position every night. Try to turn them during the night or right before you go to bed. Touch the top of the egg with a small bright flashlight. This is called "candling the egg." Use the flashlight to check if the egg is growing and progressing. It should not appear clear or cloudy when you touch the flashlight to the top of it. If this is the case, it may not be progressing well. Check the temperature and humidity in the incubator to ensure it is correct.  If the egg looks solid in the light, it is fertile and doing well. You can candle the egg again at the end of week 3 of the incubation to make sure it is still growing properly. Put the egg in a hatching tray. Adjust the temperature of the incubator to 99 degrees Fahrenheit (37.2 degrees Celsius). The humidity should be set to 88 degrees Fahrenheit (65%). Make sure the ventilation holes on the incubator are open to their maximum setting to allow the eggs to cool.  At day 26 and 27, increase the humidity to 93 degrees Fahrenheit (80%). At day 28 and 29, lower the temperature so it is at 97 degrees Fahrenheit (36.1 degrees Celsius) and the humidity is at 90 degrees Fahrenheit (70%). You do not need to help the duckling emerge from the egg. Let the duckling hatch itself by breaking through the shell on its own. If the ducking makes a hole in the egg and cannot progress because it gets stuck, carefully help the duckling out with clean hands.

Summary:
Use an egg that has been laid within one to three days. Place the egg small end down in the incubator. Maintain the correct temperature and humidity in the incubator. Turn the egg three to seven times a day. Candle the egg with a flashlight after seven days. Lower the temperature on day 25 for hatching. Let the duckling hatch on its own.