You can find the step-by-step instructions for the QR code and examples in the documentation:
Structure of the QR code For Electronic Tax Invoices
Kindly know that there is an update from SDK 3.3.0 as Tag 4 in QR Code should read the value from the amount due for payment (BT-115) if there is any adjustment towards pre-paid amount (BT-113) or rounding amount (BT-114).