Hi there,
you can use a Hook Element to add scripts to your site:
https://docs.generatepress.com/article/hooks-element-overview/
Most scripts have one of three places to be added:
1. in between the <head>
tags of your site. For this you select the WP_Head
hook
2. immediately after the opening <body>
tag. This is the WP_body_open
hook
3. before the closing </body>
tag. The is the WP_footer
hook
Here’s an example of adding Google Tag Manager:
https://docs.generatepress.com/article/implement-google-tag-manager/