You can refer the following example. This code example demonstrates the configuration and use of the CAN Tx and CAN Rx mailboxes. Five CapSense buttons are configured to control the ON/OFF status, color, and brightness of an RGB LED. This data is transmitted over the CAN, and at the CAN receiver, the RGB LED is configured to reflect the received data.
The project uses older version of psoc creator and capsense. Please use this as reference to create your own project.
There is a "Data Structure" section in the CapSense datasheet to describe the internal data like raw counts.
Some methods are described to access to the data.