The Onyxia team maintain a catalog of training and tutorials with several practical exercices that can be performed on an Onyxia instance!
By default the when you open the trainings will be open on https://datalab.sspcloud.fr (our onyxia instance) but if you don't have a Datalab acount you can edit the urls of the practical exercises so you can run them on the instance you have access to.
