How to implement YOAST breadcrumbs into child theme?

Dear Support-Team, Since YOAST SEO offers a new breadcrumbs feature I would like to implement it for pages and posts into the child theme. This are the instructions YOAST provides on this: Copy the following code into your theme where you want the breadcrumbs to be. If you are not sure, you will need to experiment with placement: Start PHP: if ( function_exists('yoast_breadcrumb') ) { yoast_breadcrumb( '<p id="breadcrumbs">','</p>' ); } END PHP NOTE: Depending on your theme you may or may not need to add in the beginning <php and ending ?> php tags. If you are not sure, your theme developer can help. Common places where you could place your breadcrumbs are inside your single.php and/or page.php file just above the page’s title. Moreover, another option that makes it really easy in some themes is by just pasting the code in header.php at the very end. Will this work? In my child theme I got: styles.css functions.php archive.php header.php single.php & page.php are missing, but maybe a header.php would do the job. Before I try anything stupid I better ask for your advice here. Regards Ulrich at: https://www.stiftung-meeresschutz.org/