Hi Francesca.
1) You can add an anchor tag with a URL to the document directly in the page content, like so:
<a href="http://path-to-your-document.pdf" target="_blank">My Document</a>
2) Add the following function to set the category on the home page:
add_action( 'pre_get_posts', 'my_home_category' );
function my_home_category( $query ) {
if ( $query->is_home() && $query->is_main_query() ) {
$query->set( 'cat', '123' );
}
}
Change “123” to the category ID you wish to display. Here is the Codex reference:
https://codex.wordpress.org/Plugin_API/Action_Reference/pre_get_posts#Show_Only_One_Category_on_Home_Page
Adding PHP: https://generatepress.com/knowledgebase/adding-php-functions/
If you’re not yet using a child theme you can download one from the above link.