Add Step to WooComerce Process Payment

i really need some help, i have been looking for ways to do this I am lost.

I created a WP plugin, Created A paiement Gateway by extending WC_Payment_Gateway but now I can't find a way to add a custom template page, I want to add a step in the payment process to execute some JS and connect to the client wallet (MetaMask).

In other words, How to add a step to the WooComerce payment process by generating a page via my plugin and when transactions is done get back to normal process ?

I really appreciate your help, a big Thank you !

public function process_payment($order_id){

    $order = wc_get_order($order_id);

    $order->update_status('on-hold', __('Awaiting MetaMask Payment','scpay-pay-woo'));

    echo $order;

    //Code redirection wp_redirect(my_custom_template_page)
    //                If my redirection is ok return this 
    return array(
        'result'   => 'success',
        'redirect' => $this->get_return_url( $order )
    //ELse return fail