Magento – adding a video to home page banner

Maria,

Your method is almost correct, you simply need give each block a unique name.

<reference name="content">
    <block type="catalog/product_list" name="featured_1" template="catalog/product/list.phtml">
        <action method="setCategoryId"><category_id>1</category_id></action>
        <block type="core/text_list" name="product_list.after" as="after" />
     </block>
     <block type="catalog/product_list" name="featured_2" template="catalog/product/list.phtml">
        <action method="setCategoryId"><category_id>2</category_id></action>
        <block type="core/text_list" name="product_list.after" as="after" />
     </block>
</reference>

Update The method above works in Magento 1.9.1.0, using the rwd/default package/theme. However does not address the OP's requirement to also display the category banner. To do this, I have revised the answer to the following:

Create this file: app/code/frontend/PACKAGE_NAME/THEME_NAME/template/catalog/category/view/multiple.phtml

(replacing package name and theme name with what applies to your site)

In it, have the following contents:

<?php
/**
 * Displays multiple category view templates along with the product list for it
 */
/* @var $this Mage_Core_Block_Template */

$category_ids     = explode(',', $this->getData('category_ids'));
$current_category = Mage::registry('current_category');

if ($current_category) {
    Mage::unregister('current_category');
}

foreach ($category_ids as $id) {

    $category = Mage::getModel('catalog/category')->load(trim($id));

    if (!$category->getId()) {
        continue;
    }

    Mage::register('current_category', $category);

    $product_list = $this->getLayout()->createBlock('catalog/product_list', 'product_list_'.$id, array('template' => 'catalog/product/list.phtml'));

    echo $this
        ->getLayout()
        ->createBlock('catalog/category_view', 'category_'.$id, array('template' => 'catalog/category/view.phtml'))
        ->append($product_list, 'product_list')
        ->toHtml();

    Mage::unregister('current_category');
}

if ($current_category) {
    Mage::register('current_category', $current_category);
}

Within the "Design" tab of your CMS page, add the following XML instructions:

<reference name="content">
    <block type="core/template" name="multiple_categories" template="catalog/category/view/multiple.phtml">
        <action method="setData"><key>category_ids</key><val>1,2</val></action>
     </block>
</reference>

Make sure to update the comma separated list of category ids with the IDs you actually want to display.

Pretty straight relation which invokes home-page-block, is Widgets.

1. Content -> Widgets -> Now click on Home Page widget. Storefront Properties -> Layout Updates -> specific page Widget Options -> Block > Home Page Block.

2. You can set/change CMS page by Stores-> Configuration-> General-> Web-> Default Pages-> CMS Home Page You can select the page by title.

   By default the page is Home Page

3. Module-Widget Module is responsible for all the code, a lot more questions can be covered if you observe the below file.

   Magento root/vendor/magento/module-widget/view/adminhtml/templates/instance/edit/layout.phtml

Where does it get its list of Pages ?

As on the above if you go to line 136

   $block->getLayoutsChooser();

  /vendor/magento/module-widget/Block/Adminhtml/Widget/Instance/Edit/Tab/Main/Layout.php

File contains

    public function getLayoutsChooser()
    {
        $chooserBlock = $this->getLayout()->createBlock(
            'Magento\Widget\Block\Adminhtml\Widget\Instance\Edit\Chooser\Layout'
 // Setting other variables
        )
   }

/vendor/magento/module-widget/Block/Adminhtml/Widget/Instance/Edit/Chooser/Layout.php

The below function will return the pages.

protected function _beforeToHtml()
{
    if (!$this->getOptions()) {
        $this->addOption('', __('-- Please Select --'));
        $pageTypes = $this->_config->getPageTypes();
        $this->_addPageTypeOptions($pageTypes);
    }
    return parent::_beforeToHtml();
}

Where the container can be rendered ?

in the layout.phtml $block->getDisplayOnContainers(); is responsible for getting all containers.

What is the container means ?

Containers are type of blocks for structured design which follows design fallback. Quick working example for create container.

which says "CMS Static Block Default Template". What's its role ?

Means it will follow static block default design

<input type="hidden" value="widget/static_block/default.phtml" name="widget_instance[0][pages][template]" disabled="disabled">

/vendor/magento/module-widget/view/frontend/layout/default.xml