message: Clarify that users need to install the S3 backend plugin
diff: @@ -27,8 +27,14 @@ catalog:
  Note the `s3-discovery` type, as this is not a regular `url` processor.
  -As this processor is not one of the default providers, you will also need to add
  -the below to `packages/backend/src/plugins/catalog.ts`:
  +As this processor is not one of the default providers, you will first need to install the AWS catalog plugin:
  +
  +```shell
  +cd packages/backend
  +yarn install @backstage/plugin-catalog-backend-module-aws
  +```
  +
  +Once you've done that, you'll also need to add the segment below to `packages/backend/src/plugins/catalog.ts`:
  ```ts
  /* packages/backend/src/plugins/catalog.ts */
  