Usage

My first view
To create a view with Limpid you just have to go to HelloLimpidModule/Config/routes.php file then set your view's route:
<?php

return [
'myview_route' => [ //--your route's name
'pattern' => '/my-view', //--the pattern that will be displayed in the url input of the browser
'command' => 'HelloLimpid_Default:myview', //---and the command that will be executed
], ]
After that, you create your module directory under app directory with the name HelloLimpidModule, and under your module you create a directoty with the name Controller where you create your controller class with the name DefaultController.php that extends from the class AppController, and finaly inside your controller create your command with the name myviewCommand()
    namespace app\HelloLimpidModule\Controller;

    use framework\core\Controller\AppController;

    class DefaultController extends AppController
    {
        /**
         * My first command command
         * As you can see you calld function should end with the word "Command"
         * so Limpid can recognize it, and also to your code clear ;)
         */
        public function myviewCommand(){
            $this->paintView('HelloLimpid:app.html.twig');
        }
    }
                
As mentioned above, to render your view you just have to call $this->paintView() and gives it the module where your view exist and it's name (Module:view.html.twig). And your view should be inside a directory called View. Limpid will parse the given string and define which command to fire in which module. 
And your view should look like this (in your case the file's name is app.html.twig):
    <!--In your file app.html.twig-->
    <!DOCTYPE html>
    <html lang="en">
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <title>{% block page_title %}{% endblock %}</title>
    </head>
    <body>
    {% block body %}{% endblock %}

    {% block js %}{% endblock %}
    </body>
    </html>
                
Simple isn't :).
And what about the css and js files, how should I call them ? Well good question, as mentioned in the architecture section, Limpid provides you a directory to store your css, js files and even your images or uploaded files, this directory called assets, and you can simply call Limpid's twig extension {{ assets('js and css files path') }} to call these files for example:
    <!--In your file app.html.twig-->
    <!DOCTYPE html>
    <html lang="en">
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <link href="{{ assets('backend/css/style.css') }}" rel="stylesheet" type="text/css">
        <script src="{{ assets('backend/js/jquery-1.10.2.js') }}"></script>
        <title>{% block page_title %}{% endblock %}</title>
    </head>
    <body>
    {% block body %}{% endblock %}

    {% block js %}{% endblock %}
    </body>
    </html>
                
In this case the file style.css is under assets/backend/css/style.css, and the file jquery-1.10.2.js is under assets/backoffice/js/jquery-1.10.2.js