Theme development

Hi all; 

i'm straggling with how to override the default template of the 'Search Form' (and the Search Form Block - same approach i guess) so to fit the html markup grouped inputs of Bootstrap 4 ? 

have a look at this default D8 html output of Search Form:

Hello everybody!
I'm trying to create a slideshow with view containing a single slide with 5 content (image + title) as in the image:

https://ibb.co/JdybpgX

The different contents must be responsive (bootstrap grid) and different sizes, i tested view slideshow, owl carousel but with no results.

Any suggestions? :)

I am trying to port a Drupal 7 theme to Drupal 8. However, as I'm trying to convert the theme over to Drupal 8, I notice that some of the regions do not show up when I "demonstrate block regions". Here is what my .info.yml file looks like:

https://pastebin.com/M940NaZn

I have a menu(working with menu token), this is working every page, but this is not working on views page (does not appear on the views page). How can I show on views page? external links are working but not in-site links are visible.

thanks.

I am trying to customize a responsive grid view in D8 using Bootstrap Grid. Code is working, but I am trying to find out if some extra divs can be removed.  

Currently I am getting

I am trying to port my Drupal 7 theme to Drupal 8. However, I am encountering the following error: 

User error: "name" is an invalid render array key. in Drupal\Core\Render\Element::children() (line 97 of /opt/drupal8.10/core/lib/Drupal/Core/Render/Element.php)

Note: I also encounter this error with the key 'title'

I have done the following during the process of converting my theme: