Installing Drupal

I referenced this page https://www.drupal.org/docs/distributions/open-social/installing-open-so... when installing open social distribution.

I performed these steps

1. forked open social source

2. Cloned my repo to my local machine

3. Downloaded and downgraded Composer to 1.9.0 due to lock compatibility issues

I’m brand new to Drupal, and to web development/hosting as a whole. I’ve had some experience maintaining Wordpress sites but I’m looking for a new challenge. 
  I started a new consulting company and registered a domain and hosting with Namecheap. 
  Namecheap hosting doesn’t come with softacular for Drupal so I manually installed.
  All the Links are getting a 404 error. I checked and .htacccess seems fine. Any other suggestions?

While trying to install Drupal 9 with Mysql 5.7.30, PHP 7.4.12, windows IIS on my local machine (Windows 10) getting the below error.

Drupal\Component\Plugin\Exception\PluginNotFoundException: The "user_role" entity type does not exist. in C:\inetpub\wwwroot\drupal\core\lib\Drupal\Core\Entity\EntityTypeManager.php on line 150 #0 C:\inetpub\wwwroot\drupal\core\lib\Drupal\Core\Entity\EntityTypeManager.php(269): Drupal\Core\Entity\EntityTypeManager->getDefinition('user_role')

Does Drupal 8 support having PostgreSQL13 as the backend on Linux? Are there any special php - or other - requirements when (hopefully) using this version of PostgreSQL?

Thank you.

I hope to have a very simple question about the best method to install Drupal 9 on a production server. I've browsed some of the topics and searched but can't seem to find a concrete answer. Installing Drupal 9 locally I have no problems. I use Docker. 

Installing Drupal 9 on a production server that has Softaculous is even easier. But I'm now dealing with another web host that doesn't have Softaculous. I could manually install Drupal 9 using FTP but that would take a long time.