Let's quick start it.

Open your current theme functions.php file and paste this code.

// Control core classes for avoid errors
if ( class_exists( 'CSF' ) ) {

  //
  // Set a unique slug-like ID
  $prefix = 'my_framework';

  //
  // Create options
  CSF::createOptions( $prefix, array(
    'menu_title' => 'My Framework',
    'menu_slug'  => 'my-framework',
  ) );

  //
  // Create a section
  CSF::createSection( $prefix, array(
    'title'  => 'Tab Title 1',
    'fields' => array(

      //
      // A text field
      array(
        'id'    => 'opt-text',
        'type'  => 'text',
        'title' => 'Simple Text',
      ),

    )
  ) );

  CSF::createSection( $prefix, array(
    'title'  => 'Tab Title 2',
    'fields' => array(

      array(
        'id'    => 'opt-textarea',
        'type'  => 'textarea',
        'title' => 'Simple Textarea',
      ),

    )
  ) );

}

How to get option value ?

$options = get_option( 'my_framework' ); // // unique id of the framework

echo $options['opt-text']; // id of field
echo $options['opt-textarea']; // id of field

Online Documentation