Once you have added Xero organisation in SmartTax, now you need to make sure that GST code in Xero is the same with SmartTax.
On the left hand side is GST code in SmartTax. On the right hand side is GST code in Xero.
You need to choose “Map to existing tax rate” to select the relevant GST code in Xero.
If you have not had the GST code in Xero, you need to choose “Create in Xero” and the GST code will be created in Xero.
Once the mapping is done, “continue to Dashboard”: