The PM must work intensively with a design team:
The interaction designer works to understand the requirements and way of thinking of the target audience, and creates a prototype, also called a wireframe, based on this understanding.
The visual designer contributes the visual interface, applied to the skeleton. Essentially, these two roles create the entire user experience, making them key components of the product team.
Finally, it is necessary to test the product with users through usability tests and generate ideas for more iterations of the design process.