if the lights do not work, you probally have the decoder plugged in backwards, just turn the plug around.
the instruction sheet has the list of cv functions and default settings for strat voltage,chuff start point and rate,as well as accel/deccel. rates, you will have to adjust the setting to tune the decoder to your loco.
I have a MRC steam decoder in an old-style, not DCC ready, Bachmann Niagara. It has run flawlessly for more than 2-years. The whistle isn't proto-typical, but it is still an awesome machine.
The factory settings are just a starting point. You will have to play with the CV settings to get the speed, acceleration/deceleration and starting voltage you want, not to mention chuff rate, whistle etc.
I have noticed that the MRC sound decoders do not noticably react to small changes in the settings for volume or speed control.
River eagle is probably right. If your lights are not working you have probably got the plug in backwards. Turn it around and if the lights are working, start tweaking the CVs until you get what you want.
Be warned, the MRC decoders, while adequate in my view, do not compare with the new Soundtraxx decoders or BLI. That said, I have several in diesels and the steamer mentioned above.
Good luck. If this is your firs sound locomotive, your are going to find it to be a real trip.
Remember its your railroad
Allan
Track to the BRVRR Website: http://www.brvrr.com/