Welcome to QuickBooks Online, John! I will guide you with your tax filing.
First, you'll want to set up your VAT in QuickBooks, so you ca assign VAT codes to your transactions.
Second, you'll need to enter your transactions with tax codes assigned to them, so they'll show up on your VAT page. To do this, you can either connect your bank account to download your transactions and add them to your books, or enter them one by one. You may check out with an accountant for alternate ways to enter your transactions with taxes.