You have seen how to apply a page layout to specific pages, but to apply a specific template to your store's home page, you can add more specific layout instructions in your theme's local.xml file.

The layout handle for the home page is cms_index_index. So, to assign the home page the one column layout, you will add the following to your Magento theme's local.xml file:

<cms_index_index>
<reference name="root">
<action method="setTemplate">
<template>page/1column.phtml</template>
</action>
</reference>
</cms_index_index>

Note, though, that the layout can be overwritten through Magento's CMS tool, so this is unlikely to work in practice. You can navigate to CMS | Pages in your Magento installation's administration panel and set your page's layout using the Layout drop-down field in the Design tab: