Instructions: 1. Input price in Bitcoins in the "Amount" field. Price is indicated on the product page, or as communicated to you by our staff. 2. Input your email address in the "Email" field. 3. Click "Pay" and follow instructions. You will be presented with a choice of crypto currencies to settle the bill. 4. After payment, send us an email to payments@zerodayengineering.com with transaction link and name of course that you want. You can also request the invoice for corporate accounting. Payments are processed within 1-2 business days. In case of technical issues, contact us by email or Telegram.