According to Baidu map query, you need to take Metro Line 7, Metro Line 3 and APM from Guangzhou South Railway Station to Xiancun. The whole journey is about 22.6 kilometers and takes about 49 minutes. The specific bus routes are as follows:

Walk120m at Guangzhou South Railway Station, get on the bus at Guangzhou South Railway Station, take Metro Line 7 (towards the south of the university), transfer to Metro Line 3 at Hanxi Changlong Station (towards Tianhe Bus Terminal), transfer to APM Line at Guangzhou Tower Station (towards the west of He Lin), get off at Women and Children Center Station (exit B) and walk 490 meters to Xiancun.