FeliX is a global system dynamics model of climate, economy, environment and society. The FeliX model has been extended recently to analyze the future dynamics of global wellbeing, indicated by the novel Years of Good Life (YoGL) metric, with respect to the interactions between global demographics, climate change, economic growth and environmental change. This technical report documents the population, economy and wellbeing modules of the FeliX model relevant for formulating global wellbeing. In addition to the model description, the report includes a detailed explanation of the baseline scenarios used for exploring global wellbeing dynamics. This document is complementary to the main publications that present the global integrated wellbeing analysis using the FeliX model, including the IIIASA Flagship Report (2023), and can be referred to as a technical guide.