Drupal 8.x

I am currently trying to get Drush working on my localhost and set an alias to my local site.
This is proving to be quite challenging for some reason
I have installed my site using composer. I have downloaded the drush-master zip via git.
I did try and run composer global require drush which appeared to work (installed drush in a composer folder in user/appdata/roaming/composer/vendor/drush/drush) It still didnt work so I added the path as a PATH environment variable.
in Git I get this message

I've looked in the online documentation (https://docs.adaptivethemes.com/) and I am a bit lost. I am also pressed for time trying to get a design working before a Tues am meeting.

What CSS / SCSS file do I need to modify in order to change the background color of a specific block region? (In my case it will be Leaderboard, Header First and Header Second)

This is driving me nuts... I need a block view with the standard monthly archive and post count:

January 2017 (3)
February 2017 (6)
etc ...

But I can not get my head around it (since D8 does not provide the archive view anymore..) .... Using content/fields ...I can not get this basic stuff together .... adding created:year and month as contextual filter gives me WSOD no matter if I use content or fields ...

I am using the Drupal 8 module "Video" (https://www.drupal.org/project/video) to insert Videos

I have put in the field to let me upload 3 files and in each of the file type fields I uploaded MP4, OGV and WEBM.

In the configuration of the entity, in the Administration of visualizations, I have:
- Make the field render HTML5 format Video Player
- Certain measures
- Auto play
- Loop
- Preload (none, metadata, auto)

With this configuration the generated HTML code is:

I have entities with image fields, and some of those fields have a "default" image.

In Twig, I get the URL of my image like this:

{{ file_url (content.field_home_header_image['#items'].entity.uri.value) }}

But how can I get the default image using Twig and no need to pre-process in the PHP theme?

Hi there,

I am new to Drupal, but upon installation I ran into the following:

An AJAX HTTP error occurred.
HTTP Result Code: 200
Debugging information follows.
Path: /drupal-8.3.5/core/install.php?rewrite=ok&langcode=en&profile=standard&continue=1&id=1&op=do_nojs&op=do
StatusText: OK
ResponseText:
Fatal error: Call to a member function setFormClass() on null in /home/dh_db2igg/mahdial-husseini.com/drupal-8.3.5/core/modules/field_ui/field_ui.module on line 74