diff --git a/sentry/variant-onbuild.md b/sentry/variant-onbuild.md
index 863bf46d0..f57800e97 100644
--- a/sentry/variant-onbuild.md
+++ b/sentry/variant-onbuild.md
@@ -5,3 +5,11 @@ This image makes it easy to custom build your own Sentry instance by copying in
 It's also possible to develop custom extensions within your `onbuild` package. If the build directory contains a `setup.py` file, this will also get installed.
 
 See the [official Sentry documentation](https://docs.getsentry.com/on-premise/server/installation/) for more information.
+
+To create your custom `sentry:onbuild` package, simply do the following:
+
+1.	Create a Dockerfile containing `FROM sentry:onbuild`
+2.	In the same directory, add your custom configuration files.
+3.	You can get copies of those files to use as templates from the [docker-sentry GitHub repo](https://github.com/getsentry/docker-sentry/).
+4.	Build your image: `docker build -t mysentry .`
+5.	Run your custom image using `mysentry` instead of `sentry`.