Drupal is a content management system written in PHP that it's free and open-source.
Before adding Drupal as a remote schema, you need to enable and configure GraphQL in your Drupal project. Check the drupal-graphql documentation to learn how to do it.
After enabling and configuring GraphQL for your Drupal project, your GrahpQL endpoint should be - <project-URL>/graphql
.
Go to your project's console in Hasura and then to the "REMOTE SCHEMAS" page. Once there:
Save it by clicking the "Add Remote Schema" button and you are done!