Please start your trial by install the add-on directly from Google Sheets or from the Google Workspace Marketplace. You can click on the "Start free trial" button in this page.
At any point during or after your trial, you can upgrade your subscription by clicking on any of the Upgrade buttons this in page, or by going to our Billing Portal directly from the add-on inside your Google Sheets. When you attempt to upgrade, you will be redirected to a checkout page hosted on Stripe (our payment processor). When you checkout, please ensure that you're using the same email address of the account you would like to upgrade with.