Installing Drupal

I just installed the latest version of D8.

The installer says,

REQUIRED MODULES

Required modules not found.The following modules are required but were not found. Move them into the appropriate modules subdirectory, such as /modules. Missing modules: 

Hello Everyone,

I have some trouble when re-install Drupal, can anyone tell me the best possible way of how to reinstall drupal 8 from ubuntu 13? After try some ways but it is making me confused!!

Many thanks.

After reading thousands of posts in the issue queue I'm about to drink the poison and learn how to install and update Drupal with composer.  I already had composer installed on my Windows 10 machine so I updated it then started reading instructions and trying to install 8.6.2 (at this writing the latest version).  

In my Windows command box I went through various permutations such as:

"composer create-project drupal-composer/drupal-project 8.x-dev --stability stable --no-interaction"

Hi all,

I have drupal 8. All worked well for a long time. Now I got this fatal error: I cant access   /admin/structure/block anymore. Message:

The website encountered an unexpected error. Please try again later.

I got the following info from my reports and I have no clue what its talking about? Anyone can tell me how to fix this? I would be so massively grateful!

Hi, it is possible to authenticate user information like (Username) and (Password) created on my website, with GameSparks?
PS: GameSparks is an Backend service for multiplayer games, more info here:
https://www.gamesparks.com/

I haven't noticed this before but I haven't installed Drupal 7 for quite a while either. We thought we could migrate to Drupal 8, but way too many issues and unported modules for that so back to 7.59 - BTW, this happened TWICE (I thought I had done something wrong in the first case)

I have zero knowledge as to what to do about these: