The prototype stage contains the Low fidelity and High fidelity designs of your proposed solutions. This slide shows steps to take when coming up with user journey maps and a low fidelity prototype.
26. Additional reading
Beginner’s Guide to UI Sketching
https://www.justinmind.com/blog/ui-sketching/
A Beginner’s Guide to User Journey Mapping
https://uxplanet.org/a-beginners-guide-to-user-journey-mapping-bd914f4c517c
User Flows
https://bit.ly/3dUps5T