created block template file what is next? Newbie

i am using drupal 6.
i copied the default block.tpl.php and renamed to my block name with the right module and delta name, following this link; http://drupal.org/node/104319

now i can see these two lines

print $block->subject;

i suppose $block->content is where i need to work.
but where can i get the information to split this and create my custom html.

please advice thanks