I want to add this at my project

[danilosilvadev]

Here it is a simple html+css using grid page.

Your example says:

Simply add the script after jQuery

I didn't understand what you mean with that.

Is it that in the head?

<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
    <script src="grid-layout-polyfill.min.js"></script>

Please i'd like more info about how to use this in my project.

[JoshuaMcKelvey]

Yes, this is how you should get the library to load into your project.