I don't know where your bus will stop, but it should be South Station or Diamond Road coach station. If it's South Station, walk to the train station (just opposite the railway, I don't know if the person asking for directions is close). There is no bus No.3 or No.34 at the train station (No.3 should be suitable).

If you get off at Diamond Road Long-distance Station, take No.3 or No.34 to Renmin Road. It's not far. Ask for directions.