AB Testing allows you to assess the effectiveness of your campaign. You can select a specific number of customers from the audience and test what would be their preferences and how effective your campaign would be. For example, you can use this to see which subject line will have better open-rate. Click on the "AB Testing" icon in the Action menu on the right side of the Audiences list.
The "Preparation of audiences for A / B Testing" window will appear.
Insert a number of contacts in one audience. This will divide your audience into three groups. Group Test A with the inserted number of contacts, the group Test B with another inserted number of contacts and the third group with the remaining contacts in your Audience.
Click on "Create A/B Test Audience" button to save your choice. After seeing the results from both campaigns, you can choose the better perfoming one and send it out to the remaining contacts from your audience - the third group.