In his contribution Policy Networks: History to the Encyclopedia of Social Network Analysis and Mining (2017), Stokman distinguishes three fundamental processes of collective decision making (persuasion, logrolling, and enforcement), and specifies conditions under which each type of process is dominant. The Python software tool Decide is a userfriendly, publicly available tool for generating, documenting and analyzing data of two fundamental collective decision making processes: persuasion and logrolling. The tutorial not only provides instructions for the use of the Python tool, but also an introduction to collective decision making theory and research and its relation with different types of social networks. Tool and examples will be illustrated using important international decision making processes, like the Copenhagen and Paris Climate Negotiations and negotiation processes in the European Union. Outline of the tutorial • Introduction to the three fundamental processes of collective decision making: persuasion, logrolling (exchange) and enforcement based on the Policy Networks: History article. • Introduction of the Python-tool Decide • Illustration of the tool and model outcomes on the basis of the data collected to predict the outcomes of the Copenhagen Climate Conference • Introduction to the stochastic extension of the earlier model • Downloading of the program on the notebooks of the participants • Exercises with Copenhagen and Paris Climate Conferences and European Union Decides datasets • Discussion of output Recommended reading: http://stokman.org/artikel/17%20Policy%20Networks_%20History%20-%20Springer.pdf