Create a page layout
Use an existing site base template as your starting point. Put shared document structure in the base and page-specific markup in blocks.
{% extends "base.tpl" %}
{% block content %}
<main>
<h1>{_ Our garden _}</h1>
<p>{_ Find out what is growing this week. _}</p>
</main>
{% endblock %}
Check which blocks your chosen base provides before overriding one. Keep the standard head and body includes so active modules can contribute scripts, styles, metadata, and browser initialization. In a custom base, use tag#all_include with the standard include names instead of copying module-specific head fragments.
In a custom base, put {% all include "_html_head.tpl" %} inside <head>. Near the end of <body>, keep {% all include "_html_body.tpl" %}, the site's _js_include.tpl, and one final {% script %} in their established order. Wires collect browser code for that final script tag; without it a page can render correctly while its buttons do nothing.