The general objective of this project is to exploit the potential of the Gaia mission, combined with the database built by our team in the last years, to bring substantial improvement in the determination of stellar distances and the early evolution of the LG galaxies. We will combine high resolution spectroscopy, optical and NIR photometric time series to distances based on Gaia DR3 to a sample of bright, nearby RR Lyrae stars. This will allow us to derive new Period-Luminosity-Metallicity and Luminosity-Metallicity relations. We will apply them to derive homogeneous distance to ~50 Local Group dwarf galaxies. This will set a benchmark for the future extension of the cosmic distance ladder. Moreover, we will derive the metallicity distribution of the target galaxies, and will perform a global study of the early chemical evolution across the Local Group. RR Lyrae stars from Gaia Dr3 will be used to characterize the Milky Way halo, combined with WEAVE data. Distance to far RR Lyrae stars will be derived using the new PLZ relation. Combined with kinematic data, we will be able to identify in the phase space the remnants of the accreted building blocks, and identify their population of RRL stars. This will in turn allow us to search for systematic differences with respect to stars formed in situ, and therefore shed light on the effect on the formation environment.