While research ethics and developing respective competencies is gaining prominence in higher education institutions, there is limited knowledge about the learning process and scaffolding during such training. The global health crisis has made the need for facilitator-independent training materials with sufficient support even more pronounced. To understand how knowledge building takes place and how computer-supported collaborative learning supports research ethics learning, we analysed: 1) how the participants’ understanding was displayed during the collaborative learning process utilising the developed ethics resource; and (...) 2) whether the scaffolding provided by the resource supported the learning process. Epistemic evidence was collected during design-based research involving 36 PhD students and researchers with supervisory experience divided into 11 groups. Data was analysed qualitatively utilising the SOLO taxonomy. The results revealed that: 1) participants displayed high levels of understanding and the need for the facilitator support decreased with the use of the online ethics resource; 2) the learners were able to evaluate their learning outcomes with satisfactory accuracy; 3) when used linearly, the online ethics resource helped learners to achieve high levels of understanding even when the scaffolding gradually faded. Based on the lessons learnt, design principles were extracted to develop research ethics competencies in higher education, and also recommendations for research ethics training were outlined. (shrink)