Hi, you can take a train Heshihao to guangzhou railway station,( besure to buy ticket for guangzhou railway station ,not guangzhou east railway station) then you can ask the people meibocheng near to railway station,there you will see interence of the Abi Waqqas Mosque, or from the square infront of the railway station you can see KFC, go to KFC side then cross the big road then you will be at the enterence of the mosque.
To grand mosque you can take a Subway Line to from yuexiu park metro station near to Abi Waqqas mosque( you can take a another exit from the mosque which you have not go in to the mosque) to Ximenkou station, then ask the people the way to Guangta road, then you will be there. have a nice trip,