One reason this challenge is confusing is that the "arrayCell" parameter looks, because of its name, like it could be a counter, or number of an index OR it could be the contents of the cell.
It is not clear to the user which this passed parameter is meant to be. Like it is suggested above, going to read about the map method is what is needed. There, I found that there is not just one, but THREE possible parameters passed. These are, "(value, index, array1)".
So, because there is just one parameter being passed in our challenge, we can see that by default, it's going to be the first of the three, or "value". Another word for the value would be the "contents" of the cell or array field. So, that is the first thing to understand.
The second thing I had trouble with was the idea that in the function we are writing, the passed parameter is not being passed TO the map method, but it's coming FROM the map method, because the map method basically just calls our new coded function each time it increments through the array we pass it.
So, in conclusion, read and study and practice or play with the map function in general, passing and logging to the console all three of the possible passed parameters (value, index, array1) - and not just the one that we're told to pass, which is "value".
Most of my comment here is just sharing my own process with solving this challenge.
I love Codeschool.com, though!