how to travel to silk street from tiannanmen square in Beijing?

Since you are new in the city, it is suggested to take a taxi to reach the Silk Market directly. From the square to that market, there is about 4.5 to 5km.
If you want to take the subway, you can walk to reach Tiananmen East Station to take the subway line 1 to reach Yonganli. Get out of the statio from Exit A, you will find the Silk Market easily.