2
not sure what you are looking for, but to simply add static content create a php file myhtml.php or whatever:
include("mainfile.php");
include(XOOPS_ROOT_PATH."/header.php");
$xoopsOption['show_rblock'] = 0;
?>
add your html here
include(XOOPS_ROOT_PATH.'/footer.php');
?>
you will need to link to this of course.