Atlassian Stash as Source Code Repository
Atlassian Stash is an just another GIT repository plus a few nice features like Pull Requests etc. A short introduction how to work with git on command line can you find on this page: https://www.atlassian.com/en/git/
Beyond, Atlassian provides a graphical client for stash called "Atlassian SourceTree". Most functionalty can be done by clicking around in the graphical user interface. More details about this application as well as a license key (CIP4 Members Only) can you find here: Atlassian SourceTree
How to develop at CIP4
Every registered user is able to work on the CIP4 Tools and Libraries. Basically this works by fork and merge repositories.
There is one master branch per repository. This branch is only writable by the lead developers of a project. In order to make changes on the source code a new branch has to be created first.
New projects can only be created by CIP4 Developers.