I'm here to help, cameronbirkbeck.
Before starting lodging BAS, we recommend you perform pre-BAS checks to make sure the accuracy of your data.
If you have authorised QuickBooks to lodge with the ATO, the installment amount will be downloaded automatically. Please view connecting QuickBooks Online with the ATO for more information about authorising QuickBooks as your software provider with the ATO.
To make any changes, I'd recommend contacting our Customer Care Support team so they can further assist you right away with this.
Feel free to comment below if you have any other questions.