ALICE ITS3: how to integrate a large dimension MAPS sensor in a bent configuration detector

The ALICE Collaboration is developing a novel vertexing detector to extend the heavy- flavour physics programme of the experiment during Run 4 by improving the pointing resolution of the tracking, particularly at low transverse momentum. It will be a detector with three truly cylindrical layers based on thin wafer scale MAPS, reaching less than 0.07% X/X0 per layer and with the innermost layer located as close as 19 mm to the interaction point. This contribution will describe the global detector integration concept, focusing on: the sensor bending procedure, the sensor electrical interconnection, the choice of the best carbon foam for light mechanical supporting structures, the studies of cooling by air flow, and the global structures mechanical characterization.