diff --git a/README.md b/README.md
index fa8821a..a3078e4 100644
--- a/README.md
+++ b/README.md
@@ -50,6 +50,14 @@ automatically build and tag images once every other week, so users have access t
 newer images *if* they would like, and admins can set default images for their
 communities as they desire.
 
+## Customizing the template
+There are two _secrets_🕵️, that must be set in the GitHub repository settings, that control authentication with the Docker image registry:
+- `QUAY_USERNAME` — a username for a service account with push privileges to a particular image repository.
+- `QUAY_PASSWORD` — a password for the service account
+
+Finally, set a _variable_📢 to specify the image prefix
+- `IMAGE_PREFIX` — the prefix that images should use, e.g. `quay.io/2i2c/example-image-stack-`
+
 ## Using older versions of images
 
 You can find the older versions of all these images by looking through the 'tags'
@@ -59,4 +67,4 @@ page on quay.io for them:
 - [Project 1 Image Tags](https://quay.io/repository/2i2c/example-image-stack-project1?tab=tags)
 - [Project 2 Image Tags](https://quay.io/repository/2i2c/example-image-stack-project2?tab=tags)
 
-We recommend using tags with a date!
\ No newline at end of file
+We recommend using tags with a date!