You may want to use `sudo` with that if it gives you permission errors.
4. Check if yarn has been installed correctly by running in a terminal the command
```bash
$ yarn --version
```
If you see the version number of yarm, you are ready to code!
5. Go to the root of this project, open your favorite terminal and run
```bash
$ yarn install
```
To work on this webui you will need a working server as well. If you've downloaded this with deemix-gui you can run in a terminal positioned inside the deemix-gui folder the command
```bash
$ yarn install-all
```
To install all dependencies for all the modules (gui, server and webui)
Note that in development mode 1 more file (`bundle.js.map`) will be created in the public folder. This file will be deleted when running the build command, so you don't need to worry about it.
If you want to add new `.js` or `.vue` files, just add them. deemix uses ES6 synthax, so you'll probably need to export some functions or variables from your new file. Files that will export and import nothing will be ignored by the bundler (rollup).
If you want to add new `.scss` (style) files, you need to import them in the main `style.scss` file. The `.scss` files **must** all start with an underscore _, except for the `style.scss` file.