The JupyterLab interface consists of the main work area (right-hand panel), the left sidebar (containing a file browser and other useful features), and a menu bar along the top.
The main work area is where Jupyter notebooks will be displayed once opened. By default, the Launcher is displayed, which allows you to open new files.
To open an existing Jupyter notebook, double-click through the folders to find a
notebook you’re interested in, then double-click the notebook to
open it in the main work area. Notebooks are indicated by the
extension. The JupyterLab interface also supports plain text and Markdown files.
To learn more about JupyterLab, visit the JupyterLab Documentation.