OOP "Ready Query" In Class - php

Question

I'm pretty new in OOP and I'm trying to build a class that will insert lines into a table by the info I give it from the actual page, it's a bit hard to explain… This is my code:
Actual page:
include_once 'Classes/New_Topic.php';
$number = 1;
$shenhav = 'shenhav';
$boring = 'boring';
$New_Topic = new New_Topic();
$query_table = 'forums';
$query_values = '`Category_ID`, `Name`, `Description`';
$query_question = '?,?,?';
$bind_param_sss = 'iss';
$bind_param_date = ''.$number.','.$shenhav.','.$boring.'';
$New_Topic->db_insert($query_table, $query_values, $query_question, $bind_param_sss, $bind_param_date);
Class:
class New_Topic
{
function db_insert($query_table, $query_values, $query_question, $bind_param_sss, $bind_param_date) {
$this->con = mysqli_connect('localhost', 'root', '', 'forum');
$stmt = $this->con->prepare('INSERT INTO '.$query_table.' ('.$query_values.') VALUES ('.$query_question.')');
$stmt->bind_param($bind_param_sss, $bind_param_date);
$stmt->execute();
return $stmt;
}
}
I know what the problem is, but I don't know how to fix it.
the problem is in $bind_param_date, again, don't really know how to explain it but I will try.
You need the line to look like this:
$stmt->bind_param($bind_param_sss, $number, $shenhav, $boring);
with the variables. And in my code it's gonna show like that, which sadly, is not gonna work cuz some reason:
$stmt->bind_param($bind_param_sss, 1, shenhav, boring);
Hope I explained it well.
How can I fix it please?