Update README

terraform/backup/README.md

@@ -10,6 +10,9 @@ The `destination` directory contains the configuration to be applied in a differ
 For now, both configurations are to be applied manually by running `terraform apply` in the respective directory. In the future,
 this should happen via a dedicated GitHub Actions workflow. 
 
-First, set up the destination account and pass the account_id of the source account as input. It returns the ARN of
-the vault that is created.
-Next, set up the source account and pass the ARN of the vault as input.
+To set up the backup infrastructure from scratch, follow these steps:
+1) Create an S3 bucket "nhse-mavisbackup-destination-terraform-state" and a DynamoDB table "mavisbackup-destination-state-lock" in the **destination** account (for Terraform).
+2) Create an S3 bucket "nhse-mavisbackup-terraform-state" and a DynamoDB table "mavisbackup-state-lock" in the **source** account (for Terraform).
+3) Set up the **destination** account by running `terraform apply` in the `destination` directory. Pass the account_id of the source account as input.
+   It returns the ARN of the destination vault that is created.
+4) Set up the **source** account by running `terraform apply` in the `source` directory. Pass the ARN of the destination vault as input.