Thank you for the help.
This is the code I ended up using to add two buttons: Sort By Newest and Sort By Oldest, that filter results by date to the search filter.
add_filter(‘uwpqsf_form_bottom’,’injecting_buttons’,”,4);
function injecting_buttons(){
echo ‘<label><input ‘.$desc.’ type=”radio” id=”taxhide” name=”date” value=”DESC”/>’.__(“Sort By Newest”,”UWPQSF”).'</label>’;
echo ‘<label><input ‘.$asc.’ type=”radio” id=”taxhide” name=”date” value=”ASC”/>’.__(“Sort By Oldest”,”UWPQSF”).'</label>
‘;
}
add_filter(‘uwpqsf_query_args’,’injecting_custom_arg’,”,4);
function injecting_custom_arg($args, $id,$getdata){
$args[‘order’] = $getdata[‘date’];//likewise sort is the name of the order input.
return $args;
}