Mode is the answer that shows up the most, for example if your numbers were 10, 10, 14, 17, 19, the mode would be 10.
You find the median by putting the numbers in order from least to greatest, and finding the number in the middle of those, for example 10, 10, 14, 17, 19, the median would be 14.
The mean is subtracting the smallest number from the largest number, using my example that would be 19-10, so the mean is 9, if that makes any sense.