diff --git a/app/controllers/admin/weeks_controller.rb b/app/controllers/admin/weeks_controller.rb
index 938b0e9..59eda1a 100644
--- a/app/controllers/admin/weeks_controller.rb
+++ b/app/controllers/admin/weeks_controller.rb
@@ -27,7 +27,8 @@ module Admin
     # POST /admin/weeks.json
     def create
       @week = Week.new(admin_week_params)
-
+      @course = Course.find(@week.course_id)
+      params[:course_id] = @course.id
       respond_to do |format|
         if @week.save
           format.js { collection }
@@ -81,7 +82,7 @@ module Admin
 
     # Never trust parameters from the scary internet, only allow the white list through.
     def admin_week_params
-      params.require(:week).permit(:name, :description)
+      params.require(:week).permit(:name, :description, :course_id)
     end
   end
 end
diff --git a/app/helpers/errors_helper.rb b/app/helpers/errors_helper.rb
new file mode 100644
index 0000000..4c846f7
--- /dev/null
+++ b/app/helpers/errors_helper.rb
@@ -0,0 +1,30 @@
+# frozen_string_literal: true
+
+# ErrorsHelper
+module ErrorsHelper
+  def error_messages(object)
+    return unless object.errors.any?
+
+    content_tag(:div, class: 'card bg-danger p-3 text-white') do
+      concat error_messages_h4
+      concat error_messages_ul(object)
+    end
+  end
+
+  private
+
+  def error_messages_h4
+    content_tag(:h4) do
+      concat content_tag(:i, '', class: 'fas fa-exclamation-circle')
+      concat " #{I18n.t('errors_ocurred')}"
+    end
+  end
+
+  def error_messages_ul(object)
+    content_tag(:ul, class: 'm-0') do
+      object.errors.full_messages.each do |message|
+        concat content_tag(:li, message)
+      end
+    end
+  end
+end
diff --git a/app/models/week.rb b/app/models/week.rb
index 25ecc48..34df9ec 100644
--- a/app/models/week.rb
+++ b/app/models/week.rb
@@ -1,8 +1,11 @@
 # frozen_string_literal: true
 
+# Weeks
 class Week < ApplicationRecord
   belongs_to :course
 
+  validates :name, presence: true
+
   scope :by_course, ->(c_id) { where(course_id: c_id) }
   scope :name_asc, -> { order('name ASC') }
   scope :name_desc, -> { order('name DESC') }
diff --git a/app/views/admin/courses/show.html.erb b/app/views/admin/courses/show.html.erb
index 5a4b713..99f6705 100644
--- a/app/views/admin/courses/show.html.erb
+++ b/app/views/admin/courses/show.html.erb
@@ -1,6 +1,4 @@
-<h1 class="h3 mb-1 text-gray-800">Kurs: <strong><%= @course.name %></strong></h1>
+<h1 class="h3 mb-1 text-gray-800">Kurs: <strong><%= @course.name %></strong> (<%= link_to raw(t('back')), admin_courses_path %>)</h1>
 <p class="mb-4"><%= @course.description %></p>
 <!-- Weeks -->
 <%= render partial: '/admin/weeks/partials/index' %>
-
-<%= link_to 'Back', admin_courses_path %>
diff --git a/app/views/admin/weeks/index.html.erb b/app/views/admin/weeks/index.html.erb
index cd79d40..e6b7c15 100644
--- a/app/views/admin/weeks/index.html.erb
+++ b/app/views/admin/weeks/index.html.erb
@@ -1,4 +1 @@
-<h1 class="h3 mb-1 text-gray-800">Kursy</h1>
-<p class="mb-4">Tutaj jakiś opis.</p>
-<p id="notice"><%= notice %></p>
 <%= render partial: '/admin/weeks/partials/index' %>
diff --git a/app/views/admin/weeks/partials/_form.html.erb b/app/views/admin/weeks/partials/_form.html.erb
index 2e62bab..082bf68 100644
--- a/app/views/admin/weeks/partials/_form.html.erb
+++ b/app/views/admin/weeks/partials/_form.html.erb
@@ -1,15 +1,8 @@
 <%= form_with(model: [:admin, week]) do |form| %>
   <% if week.errors.any? %>
-    <div id="error_explanation">
-      <h2><%= pluralize(week.errors.count, "error") %> prohibited this admin_week from being saved:</h2>
-
-      <ul>
-      <% week.errors.full_messages.each do |message| %>
-        <li><%= message %></li>
-      <% end %>
-      </ul>
-    </div>
+   <%= error_messages(week) %>
   <% end %>
+  <%= form.hidden_field :course_id %>
   <div class="form-row">
     <div class="form-group col-md-6">
       <%= form.label :name %>
diff --git a/app/views/admin/weeks/partials/_index.html.erb b/app/views/admin/weeks/partials/_index.html.erb
index 93840f6..6345983 100644
--- a/app/views/admin/weeks/partials/_index.html.erb
+++ b/app/views/admin/weeks/partials/_index.html.erb
@@ -4,7 +4,7 @@
     <div class="card shadow mb-4">
       <div class="card-header py-3 d-flex flex-row align-items-center justify-content-between">
         <h6 class="m-0 font-weight-bold text-primary">Lista tygodni</h6>
-        <%= link_to raw('<i class="fa fa-plus"></i> Dodaj Nowy Tydzien'), new_admin_week_path, { remote: true, class: 'btn btn-sm btn-primary float-right' } %>
+        <%= link_to raw('<i class="fa fa-plus"></i> Dodaj Nowy Tydzien'), new_admin_week_path(course_id: @course.id), { remote: true, class: 'btn btn-sm btn-primary float-right' } %>
       </div>
       <div class="card-body">
         <div id="ajax_form"></div>
diff --git a/config/locales/pl/pl.yml b/config/locales/pl/pl.yml
index 1ad3904..d83707d 100644
--- a/config/locales/pl/pl.yml
+++ b/config/locales/pl/pl.yml
@@ -3,6 +3,7 @@ pl:
   logout: 'Wyloguj'
   login: 'Zaloguj'
   add: 'Dodaj'
+  back: 'Wróc'
   actions: 'Akcje'
   information: 'Informacja'
   empty_list: 'Nie znaleziono żadnych elementów do wyświetlenia.'
diff --git a/config/locales/pl/weeks.yml b/config/locales/pl/weeks.yml
index 7011682..26e7bdd 100644
--- a/config/locales/pl/weeks.yml
+++ b/config/locales/pl/weeks.yml
@@ -16,3 +16,4 @@ pl:
       week:
         name: 'Nazwa'
         description: 'Opis'
+        course: 'Kurs'