ok making this what i'm saying with this. on the the course archive page it'll list all of the category to ensure that it seem like this:

"a"

  • ---apple
  • ---answer

"b"

  • ---ball
  • ---large

and so forth. which is wordpress i'm speaking about. thanks greatly

You are able to retrieve a listing of the groups while using get_categories() function. You are able to pass a range of parameters towards the function that will help you to specify what sort order you need used, amongst other things.

It will look something similar to this:

$defaults = array('type' => 'post',
    'child_of' => 0,
    'orderby' => 'name',
    'order' => 'ASC',
    'hide_empty' => true,
    'include_last_update_time' => false,
    'hierarchical' => 1, 
    'exclude' => ,
    'include' => ,
    'number' => ,
    'pad_counts' => false
);

$categories = get_categories($defaults);

For additional info on parameter values and taking advantage of the came back groups, take a look at this page within the Wordpress codex.