Assuming we’re talking about airliners:
I turn on the landing lights below 10000 ft. I slow the plane down to 200 kts at the DECEL waypoint (or in the case of the A320neo, the autopilot does it itself). From then on, I gradually slow down by however I feel fit, reaching the landing speed at about the point of catching the glideslope. I also open flaps gradually as I slow down. Finally, I lower the landing gear either ~10 NM from the airport or at the beginning of the glideslope.
I don’t know whether these practices are “correct” or not, but I’ve seen these from various simmers on YouTube. Do as you feel comfortable and after a while you’ll develop a routine for the different aircraft. Also, every approach is different, so what you do when may also differ. As long as you enjoy the sim and walk away from landings it’s all good. 