What are you trying to do with latest member? Showing in the page somewhere or anything else?
Then you've to use corresponding hook and then call it with the function. e.g. if you want it to show on header then use global_start hook and then use a function with the query to fetch the username of the latest registrant.
Yeah I want in the header so how do I write the query, sorry I'm just starting to learn!
Try the following function;
function newest_user()
{
global $cache, $templates;
$stats = $cache->read("stats");
$newest_user = build_profile_link($stats['lastusername'], $stats['lastuid']);
}
I've not tested, however I guess it should work.