I am looking for AAM BP certification. Could anyone guide me on reference material to be followed and if any other material apart from videos on helpx portal.
You can refer the below mentioned link from where you can download the exam guide which will give you a better picture on AAM BP Certification.
Audience Manager Business Practitioner
Let me know if this helps.
I would recommend reading the Audience Manager implementation guide here - Introducing Adobe Audience Manager Implementation / Installation Guide.
You may even check the Intelligent guides on Adobe Experience League - Experience League Intelligent Guidance | Adobe