We need to Pay GST on Unregistered Dealer Purchase in Payables module under GST regime. How do we ha

We need to Pay GST on Unregistered Dealer Purchase in Payables module under GST regime. How do we handle this scenario in GST regime ? The supplier will give a Invoice without any tax. We need to calculate the taxes and pay the same on behalf of the Unregistered vendor under GST Act. How can we map this scenario in GST regime