Include more PR instructions

README.md

@@ -1,2 +1,8 @@
-This repository hosts the [DOM Standard](https://dom.spec.whatwg.org/). Patch `dom.bs`
-for pull requests.
+This repository hosts the [DOM Standard](https://dom.spec.whatwg.org/).
+
+### Pull requests
+
+See the [whatwg/html README](https://github.com/whatwg/html/blob/master/README.md) for the general guidelines. Note that `source` is `dom.bs` and "Acknowledgements" is "Acknowledgments" here (I
+know). Also, the DOM Standard uses [bikeshed](https://github.com/tabatkins/bikeshed) to generate
+`dom.html`. (Do not worry if using that tool is too complicated, your pull request does not need to
+contain the generated HTML.)