update readme

README.md

@@ -10,7 +10,25 @@ Set up integration between Github and Google Cloud Platform.
 
 ## Installation
 
-Instructions on how to install and set up the project.
+1. Temporarily delete `backend.tf` so that Terraform can initialize locally.
+2. Run `terraform init`
+3. Run `terraform apply`
+4. Create a `gcs.conf` file that contains the GCS bucket name output by Terraform during apply:
+
+   ```conf
+   bucket = "tfstate-xxxx"
+   ```
+
+5. Restore `backend.tf`
+6. Run `terraform init` to migrate the Terraform state to GCS.
+7. Create a fine-grained personal access token on Github with access to this repository and the following repository permissions:
+   - Read access to metadata
+   - Read and Write access to secrets
+8. Store the Github personal access token as secret in this repository:
+
+   ```sh
+   echo "github_pat_xxx" | gh secret set GH_SECRETS_TOKEN --repo="epiccoolguy/gh-gcp"
+   ```
 
 ## Usage