You might be interested in the xDrip project. That project involves a Wixel that receives data from another device and converts it to serial using the UART. The serial data is then transmitted over Bluetooth.
If you want to know what a specific function or library in the Wixel SDK does, you should look at the Wixel SDK Documentation. The front page of that documentation also has links to other resources you might need, such as the SDCC compiler documentation and the CC2511F32 datasheet.
For debugging, I recommend using the usb_cdc_acm library to send debugging information to the computer. A good example program that uses usb_cdc_acm for debugging is the radio_sniffer app.
Probably one of the first steps in your project should be to modify the Wixel's radio settings so that the radio_sniffer app can read the data from your device and report it to a computer over USB. The radio settings used by that app are found in the radio_registers library, and you will need to edit them to make sure they are compatible with the configuration of the device you are talking to.