To do Alt + A R O on Mac in Excel, download and install Accelerator Keys, then press Option, followed by A, R, O.
Command: Connection Properties
This is how to do Alt + A R O on Mac in Excel with Accelerator Keys, the native ribbon and alt key shortcut solution for Mac users who get more done with Excel.
Alt + A R O opens the connection properties dialog for the selected data connection. Here you can configure refresh settings, control how data is imported, and manage connection parameters for external data sources.