Step 1: Understanding our goal

First thing first, we need to understand what our goal is. For the function generateRandomNumber, we need to create a function that will return a random integer every time it is called.

So in JavaScript, we have a built-in function called Math.random() which generates a random float number between 0 (inclusive) and 1 (exclusive). But, it doesn't return an integer. So we are still a bit far from our end goal but it's a good start.

Step 2: Generating a random integer within range

With Math.random(), we are able to create a random float. But we want an integer. So we could multiply the float with a big integer and we would get a float which has a big integer part.

Suppose we want an integer between 0 and 10, we would be tempted to use the code below:

var float_gen = Math.random();
var int_gen = float_gen * 10;

But we are still not there yet. The int_gen variable is still of float type and we want an integer.

Step 3: Converting float to integer

To convert a float to an integer, we have the Math.floor() function in JavaScript which returns the largest integer less than or equal to a given number.

So if we want a random number between 0 and 10, we would write:

var random_number = Math.floor(Math.random() * 10);

Now, we get an integer every time we execute the code.

Step 4: Creating a function

Wrap the code inside a function.

function generateRandomNumber() {
    var random_number = Math.floor(Math.random() * 10);
    return random_number;
}

Now, whenever we call the generateRandomNumber function, it will return a random integer between 0 and 10.

Conclusion

By using Math.random() and Math.floor() we can create a function that returns a random integer between 0 and 10. This function can be useful in a lot of cases such as in games where you need to generate an unpredictable result or in simulations where you need random input values.

The final code for the function is:

function generateRandomNumber() {
    var random_number = Math.floor(Math.random() * 10);
    return random_number;
}