Drupal 8.x

Recently I have created a 'Drupal 8 Essential Training' tutorial series. The list of topics shown below.

After browsing the list please suggest to me few more topics to be included in this 'beginner' course. Your input would be much appreciated. Thank you.

Ok, second posting! (and last so far).

In search of best practices and learnings for how PDFs are migrated, managed, related, tagged, etc. in Drupal 8? Current site hosts thousands of PDFs. How are PDFs used in other Drupal systems? What are important modules for PDF content? Other considerations?

Has the process for adding HTML to a block changed in Drupal 8?

Here is our documentation for adding our embed code to the footer, but it was using Drupal 7. A customer today mentioned that they followed these directions, and their HTML code is showing on their site (it shouldn't).

http://optinmonster.com/docs/how-to-integrate-optinmonster-with-drupal/

Hello,

I'd like to create a block that display informations on the author of the article. These informations are saved in different fields that I've created in the Users part of Drupal.

I guess I have to create a View and use contextual filters to get these fields, but I don't know how to do...

Thanks for your help !

PS : I use Drupal 8.x

EDIT : Finally found the solution

There is a form with which users can post messages type Order (Order), how to connect a button to pay by paypal to the form?