diff --git a/docs/custom_vm.md b/docs/custom_vm.md
index 0825f06..5511758 100644
--- a/docs/custom_vm.md
+++ b/docs/custom_vm.md
@@ -209,6 +209,14 @@
 $ adb unroot
 ```
 
+If virt apex is Google-signed, you need to enable the app and grant the
+permission to the app.
+```
+$ adb root
+$ adb shell pm enable com.google.android.virtualization.vmlauncher/com.android.virtualization.vmlauncher.MainActivity
+$ adb shell pm grant com.google.android.virtualization.vmlauncher android.permission.USE_CUSTOM_VIRTUAL_MACHINE
+$ adb unroot
+```
 Then execute the below to set up the network. In the future, this step won't be necessary.
 
 ```