OER Knowledge CloudJournal ArticleHuang, XiaoweiLo, Chung KwanHe, JiajuChen, GaoweiTlili, AhmedOpen Educational Resources (OER) have the potential to enhance equity in education. Many regions and education systems thus prioritise integrating these low-cost or free resources into mathematics teaching and learning. However, teachers face challenges when integrating OER into their instructional practices to prepare students for educational success. They need frameworks and guidelines to use OER and related practices (i.e., Open Educational Practices; OEP). Accordingly, we conducted a year-long synchronous online teacher professional development programme, during which teachers learned to reuse/adapt the provided GeoGebra applets and use GeoGebra features to create and integrate OER into their teaching practices. In this study, we aim to develop GeoGebra-oriented and theoretically supported guidelines for OER design and OEP tailored to mathematics teachers. To this end, we analysed teachers’ GeoGebra artefacts and their corresponding micro-teaching videos through the lens of Visual Learning Analytics (VLA) within Mathematics Discourse in Instruction (MDI) framework. In total, 650 talk turns from 14 GeoGebra-supported micro-teaching videos were analysed alongside experts’ comments. GeoGebra's interactive tools (e.g., sliders and check boxes) used in the teachers’ OER were identified, and the insights provided by VLA were explored. Based on our findings, we formulated guidelines for video-based online mathematics instruction with exemplification and explanatory talk. For example, greater integration of exemplification into teaching practices can be promoted by leveraging GeoGebra's features for observation, measurement, and construction tasks. These implications for OER design and OEP potentially contribute to equitable and quality education, in line with Sustainable Development Goal 4.20262026/04/22EnglishFrontiers in Education1118116761-19Hong KongHong Kong10.3389/feduc.2026.1811676https://www.frontiersin.org/articles/10.3389/feduc.2026.1811676/full2504-284XyesGeoGebrainstructional videomathematics educationopen educational practicesopen educational resourceshttps://www.frontiersin.org/articles/10.3389/feduc.2026.1811676/fullHuang-et-al-2026.pdfHong Kong, China, Asia