[Examples] Use the vercel CLI for with-zones (#14480)

[ch3480]

Fixes #14242
Closes #14264

Updated the readme of the `with-zones` example to use `vercel dev` instead, starting the app independently has some routing issues that don't happen on production (due to `vercel.json`), with `vercel dev` the app will match the production deployment on localhost.

examples/with-zones/README.md

@@ -3,9 +3,9 @@
 With Next.js you can use multiple apps as a single app using it's [multi-zones feature](https://nextjs.org/docs/advanced-features/multi-zones). This is an example showing how to use it.
 
 - All pages should be unique across zones. For example, the `home` app should not have a `pages/blog/index.js` page.
-- The `blog` app sets `assetPrefix` so that generated JS bundles are within the `/blog` subfolder.
+- The `blog` app sets [`assetPrefix`](https://nextjs.org/docs/api-reference/next.config.js/cdn-support-with-asset-prefix) so that generated JS bundles are within the `/blog` subfolder.
   - To also support the plain `next dev` scenario, `assetPrefix` is set dynamically based on the `BUILDING_FOR_NOW` environment variable, see [`vercel.json`](vercel.json) and [`blog/next.config.js`](blog/next.config.js).
-  - Images and other `/static` assets have to be prefixed manually, e.g., `` <img src={`${process.env.ASSET_PREFIX}/static/image.png`} /> ``, see [`blog/pages/blog/index.js`](blog/pages/blog/index.js).
+  - Images and other `static` assets have to be prefixed manually, e.g., `` <img src={`${process.env.ASSET_PREFIX}/static/image.png`} /> ``, see [`blog/pages/blog/index.js`](blog/pages/blog/index.js).
 
 ## Deploy your own
 
@@ -34,16 +34,22 @@ curl https://codeload.github.com/vercel/next.js/tar.gz/canary | tar -xz --strip=
 cd with-zones
 ```
 
-For every app, install dependencies and run the dev server:
+Install the dependencies of every app (`/home` and `/blog`):
 
 ```bash
 npm install
-npm run dev
 # or
 yarn
-yarn dev
 ```
 
-The `home` app will start in the default port (http://localhost:3000), and `blog` will start on http://localhost:4000.
+Install the [Vercel CLI](https://vercel.com/download) if you don't have it already, and then run [`vercel dev`](https://vercel.com/docs/cli?query=dev#commands/dev) in the main directory to start the development server:
+
+```bash
+vercel dev
+```
+
+Your app should be up and running on [http://localhost:3000](http://localhost:3000)!
+
+> We recommend `vercel dev` in this case instead of `next dev`, as it can start both apps at the same time and use the routes defined in [`vercel.json`](vercel.json)
 
 Deploy it to the cloud with [Vercel](https://vercel.com/import?filter=next.js&utm_source=github&utm_medium=readme&utm_campaign=next-example) ([Documentation](https://nextjs.org/docs/deployment)).