So, here's what I did.

First, I created a subdomain via the Plesk control panel. In this example, I created the subdomain "sub" in the domain "domain.com". I set the web root for "sub" to be in the same hierarchy as "httpdocs", so by default, if I put an "index.php" file in the "sub" directory, it would get served as the index for the web root of http://sub.domain.com.

Next, I ran the Laravel install with Composer:

composer create-project laravel/laravel /var/www/vhosts/domain.com/sub/ --prefer-dist

[InvalidArgumentException] Project directory /var/www/vhosts/domain.com/sub/ is not empty.

After emptying the tools directory, the install worked, but I don't think it was installed the way that I planned.

Now, I have this directory structure:

/var/www/vhosts/domain.com/sub/app /var/www/vhosts/domain.com/sub/bootstrap /var/www/vhosts/domain.com/sub/public /var/www/vhosts/domain.com/sub/vendor

When I go to http://sub.domain.com, I just see the default CentOS page.

When I go to http://sub.domain.com/public/, I though I would see the "Hello world!" output, but I got this error "Error in exception handler."

I am still confused. How should I have done this? Am I doing something incorrectly?

I understand now. I believe I need to alter my game plan.

Here's the story, and an important follow-up question at the end.

Again, I get an error:

[InvalidArgumentException] Project directory /var/www/vhosts/domain.com/ is not empty.

The directory domain.com cannot be emptied in this particular case, since it contains the actual httpdocs directory for the domain, accessible from the internet via http://www.domain.com. There is already another actual website in the httpdocs directory.

If the directory must be empty for Composer to install Laravel, then I'm guessing when I create the subdomain, I have to create to point at a subdirectory off of the one I want?

I suppose I should ask this question instead:

When I'm creating the subdomain where I want Laravel to run, I have just two fields to fill out (question at the bottom):

The subdomain name, which will be the xxx.domain.com, in this case: sub The document root, which I was putting in "sub", making the root /var/www/vhosts/domain.com/sub/, which is currently a problem.

What does the document root need to be with the intention that I want access my Laravel app from http://sub.domain.com?

I don't pretend to have extensive knowledge of web server administration, but I have been managing 2 servers for the past 3 or so years.

The only support I have is reaching out through communities like this one.

At any rate, thanks for your help.