I arrived at PEK around 4 am in the morning. I plan to visit Tiananmen Square first.

Well, the first schedule of the AE is at around 06:30. You can take it to get to Dongzhimen Station. Then transfer to line 2 to Jianguomen Station and line 1 to Tiananmen East Station, Exit A. After arriving, walk westwards to the square.

In addition, I remember that there is a Luggage Storage Counter located at the east side of Mao Zedong Memorial Hall. You can go and see. :)