Document including static assets with Pull Requests

CONTRIBUTING.md

@@ -10,10 +10,33 @@ Not sure how? Check out the [Blueprints 101](./docs/index.md).
 
 To keep the submission process smooth, please follow these guidelines:
 
-1. Submit [a Pull Request (PR)](https://github.com/adamziel/blueprints/pulls) with your Blueprint.
-2. The PR must contain a single `blueprint.json` file under the path `blueprints/your-blueprint-name/blueprint.json` (like [the examples here](https://github.com/adamziel/blueprints/tree/trunk/blueprints)).
-3. Include all static files (WXR, ZIP, JPG, etc.) listed in the Blueprint in the submitted directory of your PR, and reference them via the `https://raw.githubusercontent.com` domain.
-4. By submitting a Blueprint, you agree to license it under [GPLv2 or later license](https://www.gnu.org/licenses/old-licenses/gpl-2.0.en.html).
+Submit [a Pull Request (PR)](https://github.com/adamziel/blueprints/pulls) with your Blueprint.
+
+The PR should contain:
+
+* A single `blueprint.json` file under the path `blueprints/your-blueprint-name/blueprint.json` (like [the examples here](https://github.com/adamziel/blueprints/tree/trunk/blueprints)).
+* All the static files (WXR, ZIP, JPG, etc.) your Blueprint references. The static files must be loaded via the `https://raw.githubusercontent.com` URL pointing to your branch.
+
+For example, if you want to load `a content-export.xml` file and your branch is called `woocommerce-subscriptions`, then your PR must contain a:
+
+* A `blueprints/woocommerce-subscriptions/blueprint.json` file
+* A `blueprints/woocommerce-subscription/content-export.xml` file the Blueprint should reference as follows:
+
+```json
+{
+	"steps": [
+		{
+			"step": "importWxr",
+			"file": {
+				"resource": "url",
+				"url": "https://raw.githubusercontent.com/adamziel/blueprints/woocommerce-subscriptions/content-export.xml"
+			}
+		}
+	]
+}
+```
+
+By submitting a Blueprint, you agree to license it under [GPLv2 or later license](https://www.gnu.org/licenses/old-licenses/gpl-2.0.en.html).
 
 Make sure to correctly indent your Blueprints using tabs using a code formatter like [Prettier](https://prettier.io/) – this repository ships a `.prettierrc` file you could use. This is mostly to help the reviewers understand your Blueprint better. Every accepted and merged Blueprint will automatically be re-formatted using the `.prettierrc` file.