Hi, Ms.Pat, you can take the airport express and transfer to subway line 2 at Dongzhimen Station, then shift to subway line 1 at Jianguomen Station and get off at Tiananmen East Station.
After walking out from Exit B (northeast), you need to walk east for around 400 meters to Nanheyan Street, then turn left and walk north for around 200 meters; you will find the hotel on your left side (Nanwanzi Hutong).