Developing software environments for experiments is an iterative and time consuming process. Users usually build multiple times the image, adding every time a forgotten dependency or fixing a previously added one. As the building time of such images takes around ten minutes for full system tarballs, it does not encourage the experimenters to follow good reproducible practices when setting them up. As a result, those images cannot be rebuilt nor modified by someone else. In this tutorial, we introduce the users to NixOS Compose, a tool based on Nix and NixOS to generate and deploy reproducible environments on distributed platforms. We will first present Nix and the notions required to use NixOS Compose. As NixOS Compose can target several platforms, the users will set up their environment with lightweight containers (docker) on their local machines, allowing them to iterate quickly on their environment description. Once the environment ready with containers, users will be able to quickly test it on the Grid'5000 testbed using kexec, before generating a full system tarball.