This Good Practice Guide intends to summarize the best way to estimate the space particle fluxes and theirinteractions with the atmosphere. It provides guidance for the analysis of space radiation fluxes using satellitemeasurements and for the simulations of their interactions with the terrestrial atmosphere using the AtRIScode. It also provides the most recent results obtained at BIRA-IASB for different solar eruption events andgeomagnetic storms, especially during solar cycle 25 which has its maximum in 2025. This guide written in theframework of the EURAMET Biosphere project is made available on the project’s website www.eurametbiosphere.eu and promoted in the project’s workshops/training events so that users in space physics, radiationand atmospheric communities can easily access these documents for reference and to implement the methodsfor estimations of spatial energetic fluxes of particles and for atmospheric investigations developed in theproject.