High and ultra-high energy cosmic rays hitting the Earth's atmosphere cause extensive air showers (EAS). In recent years, these cosmic rays have been extensively studied at the Pierre Auger Observatory in Argentina. The EAS mainly consist of charged particles, especially electrons and positrons, which cause electro-magnetic emission in the MHz range by interaction with the Earth's magnetic field. To measure this radio emission, AERA, the Auger Engineering Radio Array, was deployed in October 2010 and commenced regular data acquisition in April 2011. AERA was designed as an engineering array for technology and methodology development towards future large-scale radio arrays. It will allow studies on the radio emission mechanism and the physics capabilities of the detection technique. AERA's unique site within the surface detector array (SD) of the Pierre Auger Observatory provides the possibility of coincident hybrid and super-hybrid EAS detection especially in overlap with the fluorescence telescopes Coihueco and HEAT. Besides a description of the setup, we present an overview of analyses of commissioning data taken between November 2010 and April 2011. Also, we show the first hybrid and self-triggered events detected with AERA in April 2011.