Thank you for posting in the Community, @karthik-praveen.
Let me help share some insights about preparing your BAS in GST centre.
Editing your GST period and Lodging frequency may differ depending on the GST experience you are in. Please refer to this link for the detailed steps: GST Settings Overview.
I'd also like to include this blog for more information about how to lodge BAS: Lodging BAS Using QuickBooks Online.
This should help guide you in the right direction. If you have other questions about preparing BAS, do let me know. I'm here to help.