[Plugin: Search By Category] Please ehlp

Please anyone could help me??

Where do I need to put this code:

<?php if(function_exists('sbc')){
    sbc();
} else { ?>
    // Your regular form code goes here
<?php } ?>

http://ww.wp.xz.cn/extend/plugins/search-by-category/

[Please post code snippets between backticks or use the code button.]