can anyone please tell me how can I take a bus from Kunming railway station(Nanyao St) to the stone forest?

Here are two ways for you:
1. Take a train at the railway station to Shilin (Stone Forest) first. Upon arrival, take a taxi or motorcyle to the scenic area, around 4km between. The train takes around 2h and costs CNY18.5 for a hard seat.
2. Take local public bus no. 60 from the train station to East Bus Station, where there are regular buses to the scenic area.
Bus from KM to Stone Forest takes around 1.5h and bus fare is CNY27 per person.

Thank you Mindy. It helps though.