Currently, we provide a brief (but hopelessly outdated) user guide that covers the basic functions of Ωnyx:

We have published two tutorials on Onyx:

Kievit, R. A., Brandmaier, A. M., Ziegler, G., van Harmelen, A. L., de Mooij, S. M., Moutoussis, M., … & NSPN Consortium. (2018). Developmental cognitive neuroscience using latent change score models: A tutorial and applications. Developmental cognitive neuroscience33, 99-117.

von Oertzen, T., Brandmaier, A. M., & Tsang, S. (2015). Structural equation modeling with Ωnyx. Structural Equation Modeling: A Multidisciplinary Journal22(1), 148-161.