Add below code in Child theme functions.php or WPLMS Customizer - wplms_customizer.php file :
add_action('wplms_course_nav_menu','wplms_course_remove_nav_section',100);
function wplms_course_remove_nav_section($sections){
unset($sections['members']);
unset($sections['curriculum']);
unset($sections['events']);
return $sections;
}
In above :
unset($sections['members']); removes the members section
unset($sections['curriculum']); removes the curriculum section
unset($sections['events']); removes the events section
unset($sections['news']); removes the news section
unset($sections['groups']); removes the groups section
unset($sections['forums']); removes the forums section