1) I updated XCODE app to the 13.3 version and installed the suggested Command Tools.

I use the MacOS Terminal app with the default configuration, so the default shell is 'zsh'.
Here is the contents of my .zprofile profile file in /Users/alberto, where I added the export
command for every Eiffel environment variable:

# MacPorts Installer addition on 2021-09-05_at_19:26:19: adding an appropriate PATH variable for use with MacPorts.
export PATH="/opt/local/bin:/opt/local/sbin:$PATH"
# Finished adapting your PATH environment variable for use with MacPorts.

# --- Adding appropriate variables for use with Eiffel in /Users/alberto/Eiffel_21.11.
export ISE_EIFFEL=/Users/alberto/Eiffel_21.11
export ISE_PLATFORM=macosx-x86-64
export PATH=$PATH:$ISE_EIFFEL/studio/spec/$ISE_PLATFORM/bin
# --- Finished adapting variables for use with Eiffel in /Users/alberto/Eiffel_21.11.


2) As suggested in Eiffel MacOS Setup and Installation instructions, in the 
Starting EiffelStudio section:

 ---->	'Now everything should be properly installed and you should be able to run the compiler.
	Simply navigate to /Applications/MacPorts/EiffelXX and double click the EiffelStudio icon.

	Alternatively, you can also start EiffelStudio from the command line by entering the command 	'estudio' or use the command-line eiffel compiler 'ec'.

?? I have no EiffelXX folder and no EiffelStudio icon or application in /Applications/MacPorts folder. I don't know why and if there is a way to obtain this. 



3) I entered in the Terminal window the commands you suggested:
 	sudo launchctl load -w /Library/LaunchDaemons/org.freedesktop.dbus-system.plist
 	launchctl load -w /Library/LaunchAgents/org.freedesktop.dbus-session.plist
And no issue: `Dynamic session lookup supported but failed ...` appeared. GREAT!

Now I can run 'estudio' in the Terminal window, it correctly opens the Studio app and a panel where I can open the simple.ecf file with 'Compile' ACTION and CLEAN active, as in the Tutorial. In the OUTPUTS TOOL each compilation degree appears:

'Degree 6: Examining System
Degree 5: Parsing Classes
Degree 4: Analyzing Inheritance
Degree 3: Checking Types
Degree 2: Generating Byte Code
Degree 1: Generating Metadata
Melting System Changes

Eiffel Compilation Succeeded'


4) When I click the Run button on the toolbar at the top of the EiffelStudio window the following message appears in the popup window:
     'You must compile a project first'

?? What can I do now ??