Software projects with a larger code base can be hard to maintain, and testing could therefore be a necessity. But how would one prioritize tests in their existing software project, if their project never had any tests? The purpose of this study is to find concrete steps of how to prioritize tests in a software project, independent of project type and development language. Said steps were found through two iterations of the Action Learning method. The results were found without any requirements specification, which lead to using intuition, together with code complexity, to prioritize test cases, after breaking down the project into its modules. As the study was conducted on only one specific software project, the result is limited to that specific software project until further research is conducted.