Drupal 8.x

Hey guys, I am new to drupal, here I have a problem.
I know html+css, and can make a simple website with html/css, or some framework like bootstrap. But not familar with php or other language.

Now I want to study drupal, since d8 is the newest version, I decided to start with d8. But I am confused when I reading the document, I had read theme guide in https://www.drupal.org/documentation/theme, but still don't know how to create a custom theme(which I had already done in html+css).

Drupal 8.03 here. I've spent hours on this; I need help. When I...

Rewrite Results > Override the output of this field with custom text

And I enter in the following HTML in the override field...

<strong>This is a test</strong>

My View generates the following output in my Preview...

<strong>This is a test</strong>

Instead of the bold This is a test which is the result I expected.

I using drupal 8.0.2 I got a problem when I login as admin user (Problem is only for login as admin user id=1)

It's white screen with the word "The website encountered an unexpected error. Please try again later."

I have no idea about that. And I can't do anything because I have only one id for admin.

Sorry I placed this in the wrong queue. Moving to bootstrap theme queue....https://www.drupal.org/node/2662924

I'm using Drupal Bootstrap 8x 3.0 beta2 with a sub theme. Whenever I attempt to add new content with the "save and keep published" button, instead of saving the data, it's reverting to the preview page and won't save.

I have installed the Display Suite module in Drupal 8 and whilst it appears in the Extend List the check-boxes are disabled and I am unable to enable them. Any ideas why?

Earlier today I tried to install the MailChimp plugin for Drupal 8. I couldn't get it working properly so I decided I would just go ahead and uninstall it.

However, when I navigate to /admin/modules/uninstall I get the following error: