How can I travel from Sunway airport hotel to Emerald holiday hotel (Luohu railway station) in Shenzhen

Are you sure you want to to use the subway?
If so, you can take the airport free shuttle bus line M416 to get to the Hourui Subway station, where you can take the Luobao Line to reach Luohu Station directly.
You need to get of the station from Exit A and pass the Railway Station Viaduct, you can see your hotel.
Or I think you can take the airport shuttle bus line 2 to reach the Railway Station directly without any transfer. Upon reaching Luohu Railway Station, you can walk to your hotel easily.