User Research Material: Usability Testing

This sub-issue addresses the creation of usability testing materials for the Onboarding Experience Study for Knative Eventing (#130). The usability tests aim to observe users directly as they interact with Knative Eventing, identifying specific pain points and areas for improvement.

**Tasks**:
1. Develop detailed usability test scenarios and tasks that cover the initial setup, configuring event sources, setting up triggers, and debugging.
2. Create a script for conducting the usability tests, including pre-test and post-test questions.
3. Review and refine the usability test materials to ensure they effectively capture user interactions and challenges.

**Link to Main Issue**: [Onboarding Experience Study for Knative Eventing #130](https://github.com/knative/eventing-onboarding-research/issues/130)