agnesmeil

I’m sorry, I know very little about coding. What I meant was that the post type “namaste_lesson” was already made before the buddypress activity thingy was made, and therefore it wouldn’t actually add any support to the lesson. If that makes any sense.

Either way, at the buddypress support forum they found me the solution to my problem: https://buddypress.org/support/topic/custom-post-type-comment-tracking/#post-250738

The solution:

$args=array(
	"label" => __("Namaste! Lessons", 'namaste'),
	"labels" => array (
	    "name"=>__("Lessons", 'namaste'),
	    "singular_name"=>__("Lesson", 'namaste'),
	    "add_new_item"=>__("Add New Lesson", 'namaste'),
            'bp_activity_admin_filter' => __( 'Lessons', 'namaste' ),
            'bp_activity_front_filter' => __( 'Lessons', 'namaste' ),
            'bp_activity_new_post' => __( '%1$s created a new <a href="%2$s">Lesson</a>', 'namaste' ),
	    'bp_activity_comments_admin_filter' => __( 'Comments about Lessons', 'namaste' ),
	    'bp_activity_comments_front_filter' => __( 'Lesson Comments', 'namaste' ),
	    'bp_activity_new_comment'  => __( '%1$s commented on the <a href="%2$s">Lesson</a>', 'namaste' ),
	),
	"public"        => true,
	"show_ui"       => true,
	"has_archive"   => true,
	"rewrite"       => array("slug"=>$lesson_slug, "with_front"=>false),
	"description"   => __("This will create a new lesson in your Namaste! LMS.",'namaste'),
	"supports"      => array("title", 'editor', 'author', 'thumbnail', 'excerpt', 'comments', 'post-formats', 'buddypress-activity'),
        'bp_activity' => array(
            'action_id'             => 'new_lesson',
            'contexts'              => array( 'activity', 'member' ),
            'comment_action_id'     => 'new_lesson_comment',
            'position'              => 70,
        ),
	"taxonomies"    => array("category"),
	"show_in_nav_menus "    =>  'true',
	'show_in_menu'  => 'namaste_options',
	"register_meta_box_cb" => array(__CLASS__,"meta_boxes")
);
register_post_type( 'namaste_lesson', $args );

In the function register_lesson_type() in lesson_model.php