Read the SQA instructions on the analysis step of the project, reproduced below:
The instructions on the analysis step of the project do not mention requirements capture
The Project Management topic on this website describes how real-world project managers make use of requirements capture to improve the quality of their project specification documents.
It is a good idea to identify people you know either inside school (such as teachers, staff members or other pupils) or outside school (family members, friends or contacts at a university or local business) that could act as clients or stakeholders. Using some of the requirements capture methods described in your lessons will improve your specification document too!