Observations of the large-scale structure and the spatial distribution of galaxies in the Universe indicate that galaxies are mainly located in the densest regions, such as galaxy clusters. These systems are crucial for investigating the role of environment in galaxy evolution at different epochs. In the early Universe, the progenitors of galaxy clusters are protoclusters. Therefore, the search for and identification of protoclusters is a way to investigate the formation and assembly of clusters. Using lightcone data from the Horizon Run 5 (HR5) simulation, we search for spherical regions that are protocluster candidates and will collapse into clusters by z=0. The HR5 simulation covers a wide volume on Gpc scales, with spatial resolution down to 1 kpc, allowing us to investigate the properties of protoclusters across different scales. The protocluster identification method has been tested using snapshot data and is now applied to lightcone data from HR5, with future applications to observations such as Rubin LSST.