Navigate to Email from Marketing, Create/choose an email to use, click Run a test and choose the name/winning metric/duration, click Create test.
From your Hubspot homepage, click Marketing, and then Email.
Create an email or choose the email that you want to test.
In the top left corner, click the Run a test button.
Choose a name from both versions which will help you clearly identify which one is which.
Choose what you would like the winning metric to be and how long you want to run the test for.
Click the Create test button at the bottom left.