This is a developer-level topic and isn’t required reading for normal usage of Polestar. If you’re interested in theme customization at a code level and want to find out about action hooks, see Using Action Hooks in WordPress Child Themes.
Puro offers the following action hooks for you to use:
header.php
puro_content_top
This hook is located after the puro_render_slider function which is located after the opening site-content class.