These functions are described (briefly) in the IO-manager in ibaPDA when you are using the expression builder. 
example :
NMEAConfig(10,"192.168.1.11",4001,0)
This means we are making a connection (connection ID = 10) from ibaPDA to the device 192.168.1.11 on port 4001 using a TCP connection. Debug mode is disabled.
NMEAConfig(11,"0.0.0.0",4002,1)
This means ibaPDA is waiting to receive UDP data on port 4002 on his IP address. (connection ID = 11) 
Debug mode is enabled; this means all received data will be written into the log file which you can find on the following location. This debus mode and logfile can be used during commissioning to check what NMEA sentences are available on a connection. 
C:\Program Files (x86)\iba\ibaPDA\Server\Log         (ibaPdaServer.log)


With NMEAConfig you configure the data that you want to receive. Therefore you need to first select the connection ID from above. Because in most cases there is more than 1 NMEA bus network onboard and not all data is retrieved from 1 single connection. 

Example:
NMEAConfig(10,"VDVBW",1)

This will give us the 'transverse water speed' from the connection with ID 10 (see above)
remark: we start counting at 0 !!!

The identifier "VDVBW" can be found when enabling the debug mode for several seconds to check what NMEA messages are available on that specific connection. Afterwards, you will need to look up the specific format for a sentence identifier. You can use the following reference as an example:
https://www.tronico.fi/OH6NT/docs/NMEA0183.pdf