docs: move documentations to docs (#9733)

docs/en-US/guide/dev-guide.md

@@ -0,0 +1,50 @@
+# Local Development
+
+## Bootstrap project
+
+With command
+
+```bash
+pnpm i
+```
+
+the project will install all dependencies.
+
+## Website preview
+
+With command
+
+```bash
+pnpm docs:dev
+```
+
+the project will launch website for you to preview all existing component.
+
+## Local development
+
+See [Local development guide](https://github.com/element-plus/element-plus/blob/dev/CONTRIBUTING.md)
+
+1. With command
+
+```shell
+pnpm dev
+```
+
+will start the local development environment.
+
+2. Add your component into `play/src/App.vue`
+
+> App.vue
+
+```vue
+<template>
+  <ComponentYouAreDeveloping />
+</template>
+
+<script setup lang="ts">
+// make sure this component is registered in @element-plus/components
+import { ComponentYouAreDeveloping } from '@element-plus/components'
+</script>
+```
+
+Modify `App.vue` file per your needs to get things work.