737-400 flight sim question?

The three lights are marker indicators. They light up when you pass over an outer, middle, or inner marker during an approach to a runway, especially a runway equipped with ILS. Sometimes all the markers are not there. You can adjust the aircraft radios to hear the markers also, if you wish. The outer marker is often useful; the other two less so, depending on the approach conditions and procedure. The lights have nothing to do with v-speeds.

The rotating beacon is usually turned on whenever the engines are running. It tells ground personnel that the engines are turning. Strobes are for increased visibility and are usually turned on when you enter the runway, and are turned off when you leave the runway after landing.

The three lights that you speak of are your approach lights for the ILS approach. The blue "o" light indicates the outer-marker, the yellow "m" light indicates the middle-marker, and the white "i" light indicates the inner marker. In real life flying, these have uses for the approach charts and plates, but in a home flight simulator they just have a use of marking your position along the ILS aprproach. If you want to check where the markers are, check the map or chart that is provided to you by the flight sim.

As for the lights, I am not sure if this is correct for real life planes or not, but this is what I use in my simulator (and to the best of my knowledge it's accurate, but I'm not 100% sure on that)

Rotating beacon- on before the first engine is started and on until the last engine is shut down

Navigation lights are only required between sunset and sunrise, but I use them before departure from the gate (or parking ramp) up until arrival at the gate or parking ramp.

Taxi lights are to be used while taxiing.

Take off lights are to be used upon receiving the take off clearance all the way up to 10,000 feet. The same is true for landing. Under 10,000 feet the take off lights should be on and not turned off until clear of the active runway.

I use the strobe lights in the same fashion as the take off lights, but I use them continualiously from take off until landing.