findSquare()

Step 1:

Firstly, create a function called findSquare. This function is going to take one argument. In JavaScript, we declare a function using the function keyword.

function findSquare(x) {

}

Step 2:

The next step is to calculate the square of the number that is passed as an argument to the function. This can be achieved by multiplying the number by itself. In JavaScript, we can use the * operator for multiplication.

function findSquare(x) {
  let square = x * x;
}

Step 3:

After finding the square of the number, it's time to return that value. In JavaScript, we can use the return statement to send the function's result back to the caller.

function findSquare(x) {
  let square = x * x;
  return square;
}

Step 4:

Now let's test the function. We can achieve this by creating a variable and storing the function's return value in it, then printing it to the console. JavaScript provides a console.log() function for this output.

function findSquare(x) {
  let square = x * x;
  return square;
}

let test = findSquare(5);
console.log(test);  // prints 25

Step 5:

Lastly, we simplify the function by removing the extra variable square. We can directly return the result of the multiplication.

function findSquare(x) {
  return x * x;
}

let test = findSquare(5);
console.log(test);  // prints 25

In conclusion, our function findSquare(x) takes a number as an input, calculate its square by multiplying it with itself and return the result. Please note, this simple squaring function doesn't include specific error handling, for instance, if passed a non-numeric input. For full production code, ensure to include error handling to account for different scenarios.