Radio telescopes such as MeerKAT, and in the future SKA, can map the large-scale structures using Intensity Mapping techniques for the 21 cm line. A key challenge is the subtraction of the bright foregrounds, order of magnitude stronger than the 21cm signal. It is, therefore, crucial to
assess through simulations the performance of foreground cleaning in realistic scenarios, improving
both the sky model and the telescope characterization. This Focus Week at IFPU will be the ideal framework to address these tasks of the SKA Intensity Mapping Focus Group and to discuss new simulation strategies and data analysis techniques.