Clarification on rails view/controller interaction.

I'm working through the simple ruby on rails application video.

I have 1 'statuses_controller.rb' and 5 views inside a '/statuses/' directory; '_form.html.erb', 'edit.html.erb', 'index.html.erb', 'new.html.erb' and 'show.html.erb'.

Now, I assume rails works out the controller and the views are connected to each other due to the fact that the controller name is prefixed with the same directory name containing views (statuses).

The view, which I previously thought simply displayed data, actually interacts with application though the ruby code contained in its erb tags.

Here's the loop inside 'index.html.erb':

<% @statuses.each do |status| %>
  <tr>
    <td><%= status.name + '<br/>' %></td>
    <td><%= status.content %></td>
    <td><%= link_to 'Show', status %></td>
    <td><%= link_to 'Edit', edit_status_path(status) %></td>
    <td><%= link_to 'Destroy', status, method: :delete, data: { confirm: 'Are you sure?' } %></td>
  </tr>
<% end %>

Inside my statuses_controller I have this method:

def index
@statuses = Status.all

respond_to do |format|
  format.html # index.html.erb
  format.json { render json: @statuses }
end
end

I assume all of the functionality inside 'index.html.erb' is provided by this index method, and rails knows to connect them because the view is called 'index.html.erb' and the method is called 'index'.

But I just can't get my head around what the index method is doing.

What does Status.all do?

What is the resond_to loop responding to? What is it putting inside the format variable? What does calling the html method on format do? And what about json?

The view makes more sense. I think the Status.all method returns an array of classes, the view's each loop then loops through all of the array classes, and returns information such as the name and content of each item.

I assume each status class looks something like this:

class status
    attr_accessor :id, :name, :content, :created_at, :updated_at
end

But then where does this class come from? That's what I don't get? Where? What file? Where do these attributes come from.

Also, the link_to method. It seems to take two parameters, a string, which it passes into the link html text, and a class object. My question is, does it automatically look inside for the class object for an ID attribute, and use that to append the url?