NMEA2000 is completely different from NMEA0183. The former (N2K) uses proprietary plugs and sockets. The latter requires connecting little wires together and using port 1 or 2 and choosing high speed or standard. N2k is much easier but requires additional cables in place to make it work. It's not dissimilar from a computer network where you don't just run a wire from one pc to the next, they have to go via a netwowrk switch (the n2k backbone in effect). Without special convertors, you can't mix and match the two either.
With N2k theres is no soldering or connections to make, each wire has a moulded 5 pin plug on the end. You basically have a N2k cable in your boat with a T-piece at each end and terminating resistor on each end also. You then have a drop cable from one device (gps) to the backbone connected to one t-piece, and another drop cable from the vhf to the other t-piece. You actually need a third connection into this backbone which is a power connection from your battery.
If you want to use NMEA0183 then I would suggest choosing port 1. You then need the Tx (transmit) wire of the GPS connected to the Rx (receive) wire of the VHF. You also need to connect the ground wires (negative/earth) of both devices together. That will get you GPS position data onto the VHF. If you connect VHF Tx to Gps Rx you will get DSC position data onto your GPS.
Hope this helps. Lowrance have some quite helpfull diagrams in their downloads for N2k setup. this may help