diff --git a/README.md b/README.md
index cdf5a34..330ff11 100644
--- a/README.md
+++ b/README.md
@@ -265,6 +265,7 @@ Longhorn will always try to maintain at least given number of healthy replicas f
 ### [Upgrade](./docs/upgrade.md)
 ### [Deal with Kubernetes node failure](./docs/node-failure.md)
 ### [Use CSI driver on RancherOS + RKE](./docs/rancheros.md)
+### [Restore a backup to an image file](./docs/restore-to-file.md)
 
 ## Troubleshooting
 You can click `Generate Support Bundle` link at the bottom of the UI to download a zip file contains Longhorn related configuration and logs.
diff --git a/docs/restore-to-file.md b/docs/restore-to-file.md
new file mode 100644
index 0000000..bbdf782
--- /dev/null
+++ b/docs/restore-to-file.md
@@ -0,0 +1,23 @@
+# Use command restore-to-file
+This command gives users the ability to restore a backup to a `raw` image or a `qcow2` image. If the backup is based on a backing file, users should provide the backing file as a `qcow2` image with `--backing file` parameter.
+
+## Instruction
+1. Copy the yaml template
+
+    1.1 Without backing file: Make a copy of `examples/restore_to_file.yaml.template` as e.g. `restore.yaml`.
+
+    1.2 With backing file: Make a copy of `examples/restore_to_file_with_backing_file.yaml.template` as e.g. `restore.yaml`.
+    
+        1.2.1 Set argument `backing-file` by replacing `<BASE_IMAGE>` with your base image, e.g. `rancher/longhorn-test:baseimage-ext4`.
+    
+1. Set host node on which the output file should be placed by replacing `<NODE_NAME>`.
+
+2. Specify the host path of output file by modifying field `hostpath` of volume `disk-directory`. By default the directory is `/tmp/restore/`.
+
+3. Set the first argument (backup url) by replacing `<BACKUP_URL>`, e.g. `s3://backupbucket@us-east-1/backupstore?backup=backup-bd326da2c4414b02&volume=volumeexamplename`. Do not delete `''`.
+
+4. Set argument `output-file` by replacing `<OUTPUT_FILE>`, e.g. `volume.raw` or `volume.qcow2`.
+
+5. Set argument `output-format` by replacing `<OUTPUT_FORMAT>`. Now support `raw` or `qcow2` only.
+
+6. Set S3 Credential Secret by replacing `<S3_SECRET_NAME>`, e.g. `minio-secret`.