Hi there,
Welcome to the Community. I'd be happy to assist you filing a GST return in QuickBooks.
The good thing is you can file as far back as you'd like and I'll guide you through the steps. Here's a helpful article from our Community which will show you how you can do that:
https://quickbooks.intuit.com/community/Sales-tax/File-sales-tax/m-p/261654
When recording the tax filing, you can select a previous date. I encourage you to go through the article and let me know if you've got questions. I'm here to help. :)
