The first lines in jQuery

As noted before, jQuery and jQuery UI command lie within the <script> tags.
They work in concert with html tags and css of a document.

The first jQuery line starts with $()

That prepares the script to be executed. Inside the parentheses, you can put whatever you need to apply the functions. It can be a tag such as $('div') where all div tags are affected by what you write there.
Or, it can be $(document) to apply to the entire document.
Or, $('.myclass') to apply to elements with class="myclass".
Or, $('#myid') to apply to elements with id="myid".

Most of the time you want to execute the jQuery/UI after the DOM is loaded so all the relevant elements are found. In that case, use ready().

$(document).ready()

Back to the accordion. Especially for large pages, you might include a ready command so that it can find the element to apply the accordion.

<script type="text/javascript">

$(document).ready(function() {
     $("#myAccordion").accordion();
});

</script>