Update getting-started.md

Author: jackparmer

doc/python/getting-started.md

@@ -66,9 +66,14 @@ or `conda`:
 ```
 $ conda install -c plotly plotly=5.3.1
 ```
-
 This package contains everything you need to write figures to standalone HTML files.
 
+You'll also likely want `dash` for adding widgets such as sliders, buttons, and dropdowns to your charts (see more below!):
+
+```
+$ pip install dash
+```
+
 > Note: **No internet connection, account, or payment is required to use plotly.py.** Prior to version 4, this library could operate in either an "online" or "offline" mode. The documentation tended to emphasize the online mode, where graphs get published to the Chart Studio web service. In version 4, all "online" functionality was removed from the `plotly` package and is now available as the separate, optional, `chart-studio` package (See below). **plotly.py version 4 is "offline" only, and does not include any functionality for uploading figures or data to cloud services.**
 
 
@@ -78,7 +83,7 @@ fig = go.Figure(data=go.Bar(y=[2, 3, 1]))
 fig.write_html('first_figure.html', auto_open=True)
 ```
 
-### Plotly chart in Dash
+### Plotly charts in Dash
 
 [Dash](https://plotly.com/dash/) is the best way to build analytical apps in Python using Plotly figures. To run the app below, run `pip install dash`, click "Download" to get the code and run `python app.py`.