Module development and code questions

I have two entities called Competition and Club. 

Example: Football and Chelsea. It´s possible to add to Football view a button called Create new Club, that when you click on this , you can add a new club in that competition.

I am new to drupal and need my webform submissions to be sent to my SQL server containing my database and table.  If my understanding is correct, I need to use the hook_schema() function in the Webform.install file to create a php object to represent my module submission data.  But I'm not sure where to go from there.  How do I get the submission data sent and stored in my table?

Drupal 8.9
Webform Module
 

I´m developing a module and I´m working with EVA module to attach a view to a content type. 

I´ve created a content type called 'Sports' and another called 'Clubs' and I´ve got that in each sportonly appears the clubs which their field _sport match with the nid of the corresponding sport , and the final view would be like a ranking. Finally, I´ve created another field called 'Group' and then I would like that view repeats itself depending on the group. That is to say :

I have a sport called Football and their clubs like Madrid, Barcelona, Sevilla, etc.

I´m developing a module and I would like to create a menu like menu structure. I´ve coded the my_module.routing.yml file and the my_module.links.menu.yml. I´ve all pages built in routing and their links in links.menu , that is to say, I've got the complete tree of routes made up. But I´dont get that when you click on the root link, drupal sends a `type` of menu like Structure Menu.

Attach a image for better compression! I would like to do this with the routes of my module.

I am converting code from html5 to drupal 8. I have code in html that displays a simple table with set values. Here is the table:

Label - Number Key:

Hi there,

I am an experienced test manager but completely new to Drupal as a new company uses it and I am trying to get my head around the testing options. Please forgive my ignorance if my questions don't make sense or is just dumb.

I can see that Drupal 8 makes use of PHPUnit and the documentation talks about the base classes (unit, kernel, browser, webdriver) that can be used to test different instances of Drupal instances at different levels. This all sounds great and I'm sure I shall be using some of it.