Module development and code questions

I´ve used  \Drupal::formBuilder()->getForm() to pass arguments to form and get it, but when I click on submit button , It appears The website encountered an unexpected error. Please try again later. I think that I get the form but not the methods of validation and submit of own form.

I have a button in header view of a content type, It is to add a entity with the information of the current node, that is to say, 

Hi guys, Trying to set up httpclientmanager via guzzle to make a service call to google cloud.
Installed using https://guzzle3.readthedocs.io/getting-started/installation.html

where should require 'vendor/autoload.php';
 be mentioned? I added to public_html/site/modules/http_client_manager/src/httpclient.php Constructor but still guzzle fails to load,

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.