docs: Add consumption instructions

README.md

@@ -2,7 +2,7 @@
 
 [![build-ublue](https://github.com/ublue-os/base/actions/workflows/build.yml/badge.svg)](https://github.com/ublue-os/base/actions/workflows/build.yml)
 
-A base image with a (mostly) stock Fedora Silverblue. Help us make a sweet base image: Pull requests and improvements appreciated and encouraged!   
+A base image with a (mostly) stock Fedora Silverblue. Help us make a sweet base image: Pull requests and improvements appreciated and encouraged! Scroll to the bottom to see how to make your own!  
 
 ## Usage
 
@@ -61,3 +61,23 @@ These images are signed with sisgstore's [cosign](https://docs.sigstore.dev/cosi
     cosign verify --key cosign.pub ghcr.io/ublue-os/base
 
 If you're forking this repo you should [read the docs](https://docs.github.com/en/actions/security-guides/encrypted-secrets) on keeping secrets in github. You need to [generate a new keypair](https://docs.sigstore.dev/cosign/overview/) with cosign. The public key can be in your public repo (your users need it to check the signatures), and you can paste the private key in Settings -> Secrets -> Actions.
+
+# Making your Own
+
+1. Clone this repo
+1. Ensure your [GitHub Actions](https://docs.github.com/en/repositories/managing-your-repositorys-settings-and-features/enabling-features-for-your-repository/managing-github-actions-settings-for-a-repository) and [GitHub Packages](https://docs.github.com/en/packages) are set up and enabled
+1. Change the [image name in the action](https://github.com/ublue-os/base/blob/aab8078cfdc7d2354e057a0ca4771d3a53d2df4c/.github/workflows/build.yml#L14) to match what you want to call your image
+   - Changing it to `IMAGE_NAME: beagles` will name the final image: `ghcr.io/yourusername/beagles` - so you'll likely want that to be your cool name instead of `base`
+1. Generate a keypair
+   - Install the [cosign CLI tool](https://edu.chainguard.dev/open-source/sigstore/cosign/how-to-install-cosign/)
+   - Run `cosign generate-key-pair`
+   - In your repository settings, under Secrets and Variables -> Actions
+     - Create a new secret:
+     ![image](https://user-images.githubusercontent.com/1264109/216735595-0ecf1b66-b9ee-439e-87d7-c8cc43c2110a.png)
+     - Call it `SIGNING_SECRET` and then paste the contents of `cosign.key` into the field and save it. Be careful to make sure it's the .key file and not the .pub file. It should look like this:  
+     ![image](https://user-images.githubusercontent.com/1264109/216735690-2d19271f-cee2-45ac-a039-23e6a4c16b34.png)
+     - Copy the `cosign.pub` key into the root of your repository, replacing the key you got from here.
+1. Start making modifications to your Containerfile!
+   - Change a few things and keep an eye on your Actions and Packages section of your repo, you'll generate a new image one every merge and additionally every day. 
+   - Follow the instructions at the top of this repo but this time with the `ghcr.io/yourusername/beagles` url and then you'll be good to go!
+   - Hang out in the [discussions forums](https://github.com/orgs/ublue-os/discussions) with others to share tips and get help, enjoy!