Drupal 8.x

I'm using Drupal 8.  I want to create a content type called Software Documentation.  I would like 2 of the fields to be Category and Sub-Category.  For example, Accounting may be an example of a category and Accounts Payable, Accounts Receivable and General Ledger would be sub-categories.  Now that I've created a parent/child taxonomy called Categories, I'm not sure what to do with it,  I end up with a drop-down with all parent and children items.  I want one drop-down with parents and another dynamic drop-down with children related to the selected parent.

I am developing for a Drupal 8 site where licensed trainers can post their own courses. These courses have a daterange field that contains all dates of this course. The cardinality is therefore n.
This leads to problems with filtering and sorting in views. Only the first appointment is taken into account, even if it is already in the past.

That's why I developed a custom module which implements hook_cron to check the data regularly and write the next date in the future into a hidden field. This is then used for sorting and filtering in views.

In short, I'd like to at least consider setting up a Drupal site to do these things:

I am a long-time user of Drupal but I am not a coder.  I have always used AdaptiveThemes with heavy use of DS, Panels and Views.  I want to move up to D8 and use Bootstrap.  How is the best way to build advanced looking websites using Bootstrap on D8 with minimum coding?  Are the Bootswatch themes any good? Should I just use the Bootstrap CDN? and can sites using CDN later be upgraded to SASS?  Is it better to use one of the free Bootstrap themes and build on that?

We are a community organisation  currently have a website -

It is a wordpress site and I am moving it to Drupal (ver 8.4.5, I am new to Drupal hence why posting here)

JOB 1
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I am after the Map and layout at this url or something similar) -
Creating on our Drupal Site -

JOB 2
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Configure Domain Access (module, installed) to shows Domain Access is installed

Hi, 

I have installed StarRating module in my drupal 8 website, it's under development so we are experimenting with different modules. As it turned out that Five Star module has more features but it is under development ,and when used on test site it was clear that there is a long road ahead for it's stable release. 

What I want is to show average rating for the Listing, How can we do this in drupal 8.