We'd like to go to Forbidden city, Tianament Square, Temple of Heave etc by public transport

You are suggested to visit Tiananmen Square and Forbidden City first, then visit Temple of Heaven in the afternoon. From your hotel, you can take subway line 1 from Dongdan Station and get off at Tiananmen West Station, exit C and walk to the square. After walking through the square, you will get to the Forbidden City. From the North Gate(Shenwumen) of the museum, you may take bus no. 128 to Fahuasi Station and then walk to the Temple of Heaven. If you take taxi directly, the fare is about CNY25.