@nack43 You are following the documentation from the latest version, but you are using an old version of strapi. I would recommend to upgrade your strapi to latest version, but keep in mind that you should follow all the migration guides if you want to keep the existing project:
https://strapi.io/documentation/developer-docs/latest/migration-guide/
If that’s a clean project and you don’t mind losing it, then I would recommend you to just create a new project:
npx create-strapi-app@latest new-project