This document provides an overview and agenda for a webinar on the BIG IoT project and its second open call. It introduces the project coordinators and technical manager. The agenda includes presentations on the BIG IoT architecture and marketplace, and how to apply to the second open call. It summarizes the goals of the BIG IoT project to bridge interoperability gaps between IoT platforms and foster collaboration. It provides details on the open call timeline and budget, eligible applicants, and desired proposals in smart mobility and environmental monitoring domains.