Update instructions for continuous delivery with Netlify (facebook#3971)

Author: hubgit

packages/react-scripts/template/README.md

@@ -2484,7 +2484,8 @@ With this setup Netlify will build and deploy when you push to git or open a pul
 
 1. [Start a new netlify project](https://app.netlify.com/signup)
 2. Pick your Git hosting service and select your repository
-3. Click `Build your site`
+3. Set `yarn build` as the build command and `build` as the publish directory
+4. Click `Deploy site`
 
 **Support for client-side routing:**