How to integrating PayUmoney in CodeIgniter3

public function process_payment() {
    // Load the PayUmoney library
    $this->load->library('payumoney');

    // Set payment parameters
    $this->payumoney->amount = 10; // Replace with the actual amount
    $this->payumoney->product_info = 'Test product'; // Replace with the actual product information
    $this->payumoney->first_name = 'John'; // Replace with the buyer's first name
    $this->payumoney->email = 'john@example.com'; // Replace with the buyer's email

    // Generate the payment form
    $this->payumoney->generate_form();
}

<form method="post" action="https://test.payu.in/_payment">
    <!-- Hidden fields -->
    <input type="hidden" name="key" value="<?php echo $key; ?>">
    <input type="hidden" name="hash" value="<?php echo $hash; ?>">
    <input type="hidden" name="txnid" value="<?php echo $txnid; ?>">

    <!-- Payment details -->
    <input type="hidden" name="amount" value="<?php echo $amount; ?>">
    <input type="hidden" name="firstname" value="<?php echo $first_name; ?>">
    <input type="hidden" name="email" value="<?php echo $email; ?>">
    <input type="hidden" name="phone" value="<?php echo $phone; ?>">
    <input type="hidden" name="productinfo" value="<?php echo $product_info; ?>">

    <!-- Submit button -->
    <input type="submit" value="Pay with PayUmoney">
</form>

defined('BASEPATH') OR exit('No direct script access allowed');

class Payumoney {
    public $amount;
    public $product_info;
    public $first_name;
    public $email;

    public function generate_form() {
        // Set PayUmoney parameters
        $key = 'YOUR_KEY'; // Replace with your PayUmoney key
        $salt = 'YOUR_SALT'; // Replace with your PayUmoney salt
        $txnid = substr(hash('sha256', mt_rand() . microtime()), 0, 20);

        // Calculate hash
        $hash_string = $key . '|' . $txnid . '|' . $this->amount . '|' . $this->product_info . '|' . $this->first_name . '|' . $this->email . '|||||||||||' . $salt;
        $hash = strtolower(hash('sha512', $hash_string));

        // Pass variables to the view
        $data = array(
            'key' => $key,
            'hash' => $hash,
            'txnid' => $txnid,
            'amount' => $this->amount,
            'first_name' => $this->first_name,
            'email' => $this->email,
            'product_info' => $this->product_info,
        );

        $this->load->view('payment_form', $data);
    }
}