Added instructions for Codespaces

Author: dfreniche

docs/setup/index.mdx

@@ -23,6 +23,9 @@ sidebar_position: 2
 This section will cover the required notebook operations that must be fulfilled to run the challenges.
 
 ### 1. Install Atlas CLI on the notebook environment.
+
+Run the 1st cell in the notebook to install the Atlas CLI. If you're running the notebook in a Codespace you'll be prompted to install a Python environment and Jupyter Notebooks support. Select the Python Kernel when prompted.
+
 ```python
 # Install atlas-cli