Saving in two tables from one form / first implementation - no insertion / second - no implicit conversion of Symbol into Integer

I want to insert into two database tables by clicking on a button. And there are several problems:

First Problem:

Models:

class Dish < ApplicationRecord
  
has_many :courses
  
has_many :days, through: :courses
  
has_many :order_items
  
accepts_nested_attributes_for :courses

end

class Course < ApplicationRecord
  
belongs_to :day
  
belongs_to :dish

end

Controller:

class DishesController < ApplicationController

  
def new
    
@dish = Dish.new
    
@dish.courses.build
  
end

  

def create

    @dish = Dish.new(dish_params)

    if @dish.save

      redirect_to '/dashboard'

    else

      render 'new'

    end

  end


 
 private def dish_params
 
   params.require(:dish).permit(:id, :name, :description, :price, courses_attributes: [:id, :name])

  end


end

Views:

<div class="new dish">

  <%= form_for @dish do |d|  %>

  <%= d.text_field :name, :placeholder => "Dish name" %>

  <%= d.text_area :description, :placeholder => "Description" %>

  <%= d.text_field :price, :placeholder => "Dish price" %>

  <%= d.fields_for :courses do |c| %>

      <%= c.text_field :name, :placeholder => "Course name" %>

  <%= d.submit "Save" %>
</div>

<% end %>

<% end %>

After pressing the Save button, there is no insertion into the database. no redirection to '/ dashboard' occurs, the form is rendered as written in the controller. Here is the log:

Processing by DishesController#create as HTML
  Parameters: {"authenticity_token"=>"fNbaoB4w+OINn17HQ0CdwAothP8PTzR7XPYy4oy5kHpFiCUOXY4T2hOFMbrmObXFaVdI6R1jPE2/K+piXPvymQ==", "dish"=>{"name"=>"aa", "description"=>"aaa", "price"=>"1", "courses_attributes"=>{"0"=>{"name"=>"main course"}}}, "commit"=>"Save"}
  Rendering dishes/new.html.erb within layouts/application
  Rendered dishes/new.html.erb within layouts/application (Duration: 2.2ms | Allocations: 464)
[Webpacker] Everything's up-to-date. Nothing to do
Completed 200 OK in 32ms (Views: 21.5ms | ActiveRecord: 0.0ms | Allocations: 6607)

If I change the view to:

<div class="new dish">

  <%= form_for @dish do |d|  %>

  <%= d.text_field :name, :placeholder => "Dish name" %>

  <%= d.text_area :description, :placeholder => "Description" %>

  <%= d.text_field :price, :placeholder => "Dish price" %>

  <%= d.fields_for :courses_attributes do |c| %>

      <%= c.text_field :name, :placeholder => "Course name" %>

  <%= d.submit "Save" %>

</div>

<% end %>

<% end %>

then I get

TypeError (no implicit conversion of Symbol into Integer):
app/controllers/dishes_controller.rb:9:in `create'

And here is a log:

Processing by DishesController#create as HTML
  Parameters: {"authenticity_token"=>"jE7DMuPcyEo403MKrxjO2KySlM3cA/t9ZjGYNnAUlAu1EDycoGIjcibJHHcKYebdz+hY284v80uF7EC2oFb26A==", "dish"=>{"name"=>"xxx", "description"=>"tt", "price"=>"1", "courses_attributes"=>{"name"=>"first course"}}, "commit"=>"Save"}
Completed 500 Internal Server Error in 2ms (ActiveRecord: 0.0ms | Allocations: 934)

The second problem is at the level of theory and I have not yet begun to solve it. I do not yet understand how, without filling the form with values after clicking the button, throw the dish_id and day_id attribute values into the courses table. In the course table, I have several columns: dish_id, day_id, name.

May you help me please? Why there is no insert into two tables in first problem?