Revert "Update README.md"

This reverts commit 1f2a62a.

Author: justinjung04

README.md

@@ -5,3 +5,55 @@ WebViewer UI sits on top of [WebViewer](https://pdftron.com/webviewer), a powerf
 ![WebViewer UI](./assets/webviewer-ui.png)
 
 This repo is specifically designed for any users interested in advanced customizations. With the source code access, it gives developers full control to customize & style the UI, build custom controls & logic, integrate into workflows, or build a UI from scratch.
+
+## Initial setup
+
+To work with this repo, you must download the latest WebViewer and link it to this repo.
+
+1. Download [WebViewer](https://pdftron.com/webviewer).
+2. Follow steps from [forking WebViewer](https://pdftron.com/documentation/web/guides/advanced-customization/forking-and-setting-up-the-sync).
+
+Now you can navigate to `WebViewer/lib/ui` and run the commands to install, run and build.
+
+## Install
+
+```
+npm install
+```
+
+## Run
+
+```
+npm start
+```
+
+## Build
+
+```
+npm run build
+```
+
+## Project structure
+
+```
+src/
+  apis/            - APIs exposed in myWebViewer.getInstance()
+  components/      - React components
+  constants/       - JavaScript or CSS constants
+  core/            - APIs from the Core
+  event-listeners/ - Listeners for the Core events
+  helpers/         - Reused functions
+  redux/           - Redux files for state managing
+```
+
+## API documentation
+
+See [API documentation](https://pdftron.com/documentation/web/guides/ui/apis).
+
+## Contributing
+
+See [contributing](./CONTRIBUTING.md).
+
+## License
+
+See [license](./LICENSE).