How do I know how much I have collected taxes this month?

With EAS you will always have knowledge of your VAT liabilities.

EAS Dashboard shows your collected EU/UK VAT in real-time.

You can access the EAS Dashboard at

When you've accessed the Dashboard, on the landing page you'll see the amount of EU/UK taxes you have collected from your customers.
EAS invoices you for the collected IOSS VAT once a month.