To check the statistics of an A/B test, click on the three dots behind the newsletter and choose the "A/B test results" option. The A/B test's dashboard with all the results will appear. This is your dashboard for A/B testing:

To see the usual statistics for variant A, all the data you see above is clickable. For example, you can click on 'variant A', but also on 'generated revenue', 'sent emails', 'number of orders', 'open rate', 'click rate' and 'unsubscribe rate'. When you click on those, you will automatically be taken to the statistics of that variant.