youtube-channel-manager/YtManagerApp/templates/YtManagerApp/main_master_detail.html

{% extends "YtManagerApp/main_default.html" %}

{% block body %}

    <div class="row">
        <div class="col-sm-3">
            {% block master %} 
            {% endblock %}
        </div>
        <div class="col-sm-9">
            {% block detail %} 
            {% endblock %}
        </div>
    </div>

{% endblock %}