Accessibility of digital services needs to be improved, in particular for users with cognitive and learning disabilities. Our focus is on digital design patterns that have the potential to increase comprehension for users with low cognitive and reading skills by combining short and simple text with effective design. We conducted a case study with 43 easy-to-read (ETR) users and 12 university students in a control group in which users select a theater play, find a date, and order tickets. In a participatory design process with four co-researchers and a User Experience (UX) expert, we created test material with high ecological validity. Subsequent testing collected quantitative and qualitative data to provide a clear picture of the context of use, the differences in success of the three variants, and the challenges of a multi-step ordering process. Our contributions are an enhanced participatory design process involving UX experts, insights into ETR users' context of use, and proposals for cogni-tively accessible design patterns for ticket selection, appointments, and an exemplary simplified ordering process that can be applied to similar digital services. * First author This work is licensed under a Creative Commons Attribution 4.0 International License. CHI '26,