ROR5: 'param is missing or the value is empty' error with adding Bookmarks

I have an app where users can ask questions and bookmark certain questions. I'm done with the users, questions, and answers, so I've added a BookmarkController & Bookmarks model. At first, I considered using associations, but my app has a few associations already so I'm (or I've attempted at) using query parameters such as user_id and question_id to fetch bookmarks.

The structure is a bit like StackOverflow. A user navigates to a single question view and bookmarks it on that page. This creates a new bookmark model containing the user_id of current_user and the question_id. The user can go to his profile to view all the questions he bookmarked, fetched using his user_id. (Answers cannot be bookmarked. Only questions.)

I've been getting a 'param is missing or the value is empty: bookmark' error, although I have followed similar steps I did for my QuestionsController. It would be great if someone could help me out in identifying what's wrong/bad about my code!

rake routes (first part omitted)

bookmark_question PUT    /questions/:id/bookmark(.:format)                  questions#bookmark
questions GET    /questions(.:format)                               questions#index
                 POST   /questions(.:format)                               questions#create
    new_question GET    /questions/new(.:format)                           questions#new
   edit_question GET    /questions/:id/edit(.:format)                      questions#edit
        question GET    /questions/:id(.:format)                           questions#show
                 PATCH  /questions/:id(.:format)                           questions#update
                 PUT    /questions/:id(.:format)                           questions#update
                 DELETE /questions/:id(.:format)                           questions#destroy

route.rb (excerpt)

# Questions
get '/questions/:id' => 'bookmarks#create'

show.html.erb (questions#show)

<% if current_user %>
  <%= link_to "Bookmark", :controller => 'bookmarks', :action => 'create' %>
<% end %>

BookmarksController

class BookmarksController < ApplicationController 

def new
    @bookmark = Bookmark.new
end

def create
    @question = Question.find(params[:id]) # when I delete this line, I get a new error - "undefined local variable 'params'"

    @bookmark = Bookmark.new(bookmark_params)
    @bookmark.user_id = current_user.id
    @bookmark.question_id = @question.id
    @bookmark.save 
    redirect_to @question
end

def destroy

end

private
    def bookmark_params
       params.require(:bookmark).permit(:user_id, :question_id) 
    end
end

Bookmark model

class Bookmark < ApplicationRecord    
  validates :user_id, presence: true
  validates :question_id, presence: true
end

QuestionsController (at the moment, contains no reference to Bookmarks. I thought so because I did the routing, but this might be where I'm going wrong)

class QuestionsController < ApplicationController
def index
    @questions = Question.all
end

def show
    @question = Question.find(params[:id])
    @answers = Answer.all

    # Delete only appears when no answers
    @deletable = (current_user== User.find(@question.user_id)) && (@question.answers.all.size==0)
end

def new
    @question = Question.new
end

def create
    if logged_in?
        @question = Question.new(question_params)
        @question.user_id = current_user.id
        @question.save 
        redirect_to @question
    else 
        redirect_to login_path
    end
end

def destroy
    @question = Question.find(params[:id])
    @question.destroy

    redirect_to root_path
end

private
  def question_params
    params.require(:question).permit(:picture_url, :country, :educational_level, :topic)
  end

end

profile index.html.erb (just for ref)

<% if (@bookmarks.count == 0) %>
///                   
<% else %>
  <%= @bookmarks.each do |bookmark| %>
    <!-- Show bookmark content here like Question.find(bookmark.question_id) etc -->
  <% end %>
<% end %>

I have looked a the previous qns that have the same error as me. But they were all using associations. I hope to not use associations as the bookmark model only needs to keep a record of the user id and qn id.

UPDATE

So, referring to the answers given, I updated my erb to:

<% if logged_in? %>
  <%= link_to "Bookmark", :controller => 'bookmarks', :action => 'create', bookmark: {user_id: current_user.id, question_id: @question.id} %>
<% end %>

hence specifying the controller and action (and the params) that need to be directed. But rails sends an error:

No route matches {:action=>"create", :bookmark=>{:user_id=>2, :question_id=>4}, :controller=>"bookmarks", :id=>"4"}

So I assume it was a routing problem. As Pavan suggested, I did consider nesting my resources, but the nesting is already one level deep, as such:

resources :questions do
  resources :answers
end

And I reckon doing something like:

resources :questions do
  resources :bookmarks # or resources :bookmarks, only: create
  resources :answers
end

won't work. (And it didn't :( )

I'm not so sure how to get this routing problem fixed (tried Googling). Thanks.