I've got a DF150 hooked up to the network, running digital gauges and a SIMRAD NSS.

Very Easy, but method depends if you have the NMEA2k digital gauges or not.

If digital, plug engine interface cable into end of standard harness (2 plugs, 1 for data, 1 for trim sensor).

(If you already have an analog trim gauge, you need to decide whether you want digital trim, in which case you'll lose the analog gauge.)

Then connect other end of interface into NMEA2k backbone via the t-Piece. 

(I'm assuming you know enough to have already set up the network backbone - if not, you really should get some help)

I prefer to configure the interface via the gauges (i.e. choose engine year, model), then set up boat settings (fuel capacity etc etc).

Your HDS should then read the info from the configured interface and start showing the info on the telemetry / gauge screen.

If you DON'T have the digital gauges, and still want to use the analog gauges you need to connect the sensor at the engine.

Data Connector is adjacent to the analog plug connection on the front / top of the Port side of the engine - same shape etc, just different colour (can't remember what).

Then you have to feed it through the big engine cable grommet, then transom / splashwell etc and connect it into the backbone, which will need to reach the rear of the boat, unless you got a harness extension.

Leave the analog trim connected, the digital trim options on the HDS suck ass.

cheers for that dizzy, i have been given the run around on this by the supplier, at least thats my take on it, (probably just me being dumb assed) but has allways been to hard to explain or more to the point they are allways too busy (pisses me livin up here sometimes, i like face to face). I apreciate your time spent explaining to me, hope you get a feed over Easter.