hi, how to go from Guangzhou baiyun international airport to rosedale hotel? is the metro open 24 hours a day?

You can take the subway line 3 to Jiahewanggang Station and then change to line 2 to Changgang Station. Get out of the station from Exit C2, you can see your hotel.
The metro is not open 24 hours, so if you reach the airport at midnight, you need to use other methods.