[CONTRIBUTING] Move instructions for starting the docs earlier in the…

… file (#23801)

CONTRIBUTING.md

@@ -72,6 +72,20 @@ git push -u origin HEAD
 
 The core team is monitoring for Pull Requests. We will review your Pull Request and either merge it, request changes to it, or close it with an explanation.
 
+### Trying changes on the documentation site
+
+The documentation site is built with Material-UI and contains examples of all the components.
+This is a great place to experiment with your changes.
+
+To get started:
+
+```sh
+yarn start
+```
+
+You can now access the documentation site [locally](http://localhost:3000).
+Changes to the docs will hot reload the site.
+
 ### How to increase the chance of being accepted?
 
 CI runs a series of checks automatically when a Pull Request is opened. If you're not
@@ -180,25 +194,6 @@ on their a11y-tree membership makes no difference. The queries where this does
 make a difference explicitly include this check e.g. `getByRole('button', { hidden: false })` (see [byRole documentation](https://testing-library.com/docs/dom-testing-library/api-queries#byrole) for more information).
 To see if your test (`test:browser` or `test:unit`) behaves the same between CI and local environment, set the environment variable `CI` to `'true'`.
 
-### Trying the changes on the documentation site
-
-The documentation site is built with Material-UI and contains examples of all the components.
-This is a great place to experiment with your changes.
-
-To get started:
-
-```sh
-yarn
-yarn docs:dev
-```
-
-You can now access the documentation site [locally](http://localhost:3000).
-Changes to the docs will hot reload the site. If you make changes to TypeScript files
-in the docs run `yarn docs:typescript --watch` in a separate terminal.
-
-Where possible, please add tests for any changes you make.
-Tests can be run with `yarn test`.
-
 ### Updating the component API documentation
 
 The component API in the component `propTypes` and under `docs/pages/api-docs` is auto-generated from the JSDOC in the TypeScript declarations.