Thanks for the time you spent helping us.
The explanation is really fine but even this, something is still not 100% clear to me.
I noticed that by building the excitement/layout/standard.php step by step following the provided explanation, the user build a file that is different from the one provided "for reference" at the end of the paragraph.
Moreover, even by accepting the code given "for reference" what I get is the error described in the attachment.
May I ask how to get out from it?
Thanks in advance.