I would highly recommend reading the MSA booklet before you attempt to write the CDR.
You can write your career episodes on Academic Projects, Training, Industrial visits, and Work experience (provided you can submit work exp documents).
When you decide to write a career episode, ask yourself following questions before you start writing and proceed if you answer yes to all of them.
1. Did you use the knowledge of your domain in this project?
2. Would you be able to claim a majority of the competencies of an Australian Engineer listed by EA?
3. If asked for documentation/proofs, would you able to provide those?
4. Below are the tasks of a Mechanical Engineer. according to Anzsco Code 233512 Did you perform any of these duties during this project?
->Studying functional statements, organisational charts and project information to determine functions and responsibilities of workers and work units and to identify areas of duplication
->Establishing work measurement programs and analysing work samples to develop standards for labour utilisation
->Analysing workforce utilisation, facility layout, operational data and production schedules and costs to determine optimum worker and equipment efficiencies
->Designing mechanical equipment, machines, components, products for manufacture, and plant and systems for construction
->Developing specifications for manufacture, and determining materials, equipment, piping, material flows, capacities and layout of plant and systems
->Organising and managing project labour and the delivery of materials, plant and equipment
->Establishing standards and policies for installation, modification, quality control, testing, inspection and maintenance according to engineering principles and safety regulations
->Inspecting plant to ensure optimum performance is maintained
->Directing the maintenance of plant buildings and equipment, and coordinating the requirements for new designs, surveys and maintenance schedules
5. Lastly, (most important one) does this project make you a Mechanical Engineer?