Hi,
First off, enable left and right sidebar.
https://docs.generatepress.com/article/sidebar-layout-overview/
or if you’re using a layout element:
https://docs.generatepress.com/article/layout-element-overview/
We can then hook scripts and tags using Hook element.
https://docs.generatepress.com/article/hooks-element-overview/
As for where the hooks are placed, you can follow this documentation.
https://docs.generatepress.com/article/hooks-visual-guide/
For the one under centered nav, I believe you can use ‘generate_after_header’.
As for the left and right sidebar, I believe you can manually add on Appearance > Widgets using Custom HTML places on left and right sidebar widget areas.