Development of a Plugin and Stuck at the Beginning

I’ve created the initial page, and got it to show up in the main plugin list, and can activate and deactivate it.

when it’s activated, it just puts plain text centered above the header, and i am trying to get the text from the plugin to show where the text for the posts/blog goes on the other pages.

what do i have to do from here. all of the websites i have found for creation of the plugin just goes up to the point where i am at now.

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I have a page with the code {GOLFSCORE} as the content, and here is the code for the plugin.

add_action('init','scoring_insert');

// Function to deal with loading the Information into pages
function scoring_insert($content)
{
  if (preg_match('{GOLFSCORE}',$content))
    {
      $golf_output = GolfScoringSystem();
      $content = str_replace('{GOLFSCORE}',$golf_output,$content);
	}
  return $content;
}

function GolfScoringSystem()
{
	$golf_body .= 'Hello World';
	return $golf_body;
}