Installing Comma

The standalone IDE

Linux

Download the tar file.
Extract it (tar xfz comma-blah.tar.gz)
Change into the extracted directory
Run bin/comma.sh

Once running Comma, the Tools menu allows for creating a command line runner (for example, in /usr/bin/comma) as well as a launcher/desktop shortcut.

Also see the file Install-Linux-tar.txt for further information.

Windows

Download the setup executable.
Run it to install Comma.

MacOS

Download the macOS version
In the dialog, either choose Open with DiskImageMounter, or download it and double-click the .dmg file in your downloads folder
Drag-and-drop the Comma icon on the left to the Applications folder on the right
After the copying is done, Comma is installed! You can find it via Spotlight or Launchpad.

The plugin

Download the plugin zip file
In IntelliJ, open the Settings (File, then Settings)
Go to the Plugins part of the settings
Click Install plugin from disk...
Locate the zip file and click OK
You will be prompted to restart the IDE. Do so to activate the plugin.
For symbol completion from external modules and various other features, a Raku compiler should be installed and associated with the IDE. To do this, open the Tools menu and choose Setup Raku SDK.