In [1] you can find how to publish data to WSO2 BAM 2.4.0. There, first you should create a stream (which is a predefined set of fields to be published) using REST API. Then you can send data to BAM via REST API. All the data will be saved in Cassandra where you can analyze data in it using a Hadoop cluster and summarize data. In most cases summarized data is stored in RDB where these data can be visualizes in a dashboard or generate a report.
[1] http://docs.wso2.org/display/BAM240/Sending+Events+through+the+REST+API