Breadcrumbs plugin issue

I installed the Yoast SEO plugin and am currently busy setting up the breadcrumbs option. I was able to successfully implement the code into the single.php file, however the breadcumb appears above the white page. So in the grey area, between the menu and the white section where the content is. On which .php file and where do I need to paste the code in order for this to appear in the white section, where 'previous' and 'next' buttons are visible in posts? Thanks in advance