Refer to the link Figma Tutorial
Figma Design System is a Free UI Design and Prototype Tool. The Youtuber explains on:
- Design tools to create mobile app screen layout
- Navigations / Screen Transitions / Workflow via Protytype feature; experience how your actual app will work later
- Team members can comment (on specific UI e.g.) and comment can be viewed by all project team
This video also introduces Material website, icon/component resources for UI design
