New to vBulletin and PHP - what is the lifecycle of a request?

[HootinHoller]

Where are templates stored, etc. I've found docs on the pieces-parts, but haven't found how they hang together. I'm on 4.2.3

I typically work on JEE/JSP-faces tech stack. I'm having trouble seeing the big picture about how mods hang together. I understand hooks and callbacks. But how do I find the hook I need. It feels like I'm missing something obvious.

I haven't found a programming primer that describes the lifecycle of vBulletin.

Firefox, showed me the page structure below when I clicked 'New Posts':

...
<div class="body_wrapper">
    <div id="breadcrumb" class="breadcrumb">
    <form id="notices" class="notices" method="post" action="profile.php?do=dismissnotice">
    <div id="pagetitle">
    <div id="above_searchresults" class="floatcontainer">
    <form id="search_inlinemod_form" method="post" action="inlinemod.php">
        <input type="hidden" value="/search.php?searchid=2659" name="url">
        <input type="hidden" value="" name="s">
        <input type="hidden" value="1450912181-94f517a9b74949b6bb0c5b7bec54ff4d7b84b487" name="securitytoken">
        <input type="hidden" value="" name="forumid">
        <div id="thread" class="block searchresults">
            <h2 class="searchlisthead">
            <div class="blockbody">
                <ol id="searchbits" class="searchbits" start="1">
                    <li id="thread_854" class="imodselector threadbit dot new title_editable" title="testing one two">
                </ol>
            </div>
...

What I'm trying to do is fetch a results list of postings like the 'New Posts' and replace the blockbody div held in the thread div.

How do I track down the hook I need? How do I add it to the navigation tree?

Is there a developer primer? My google-fu has failed me.