Formation and propagation of the coronal mass ejections are studied widely for space weather forecasting applications. During the ascending solar cycle, various types of complex CME formations can be observed that haven't been observed before by SOHO-LASCO and STEREO-A&B Coronographs. In this study the 17 May 2012 CME event that caused the first Ground Level Enhancement Event of Solar Cycle 24, has been investigated. Event is classified as a nested CME and Triangulation Method is used to derive its source region properties. The Event has been associated with a type-II radio burst and an M-class flare. The ENLIL model from NASA Community Coordinated Modeling Center has been run for the event and a comparison with real time data is provided for the propagation of the CME. A naive MHD model is constructed to simulate the shape and propagation of the nested CMEs. The study is in accordance with former studies that propose a "twin CME" scenario for the event and associates the nested and twin CME phenomena.