Prototyping turns your sketches into interactive flows. Link frames together, define transitions, and preview your design.
When you open the Prototype Sidebar/Panel, the canvas displays arrows and icons representing the your prototype flow:

The starting frame is always marked with a Play icon. To change the first frame:
Select any object in the canvas, then select an action:
<aside> <img src="/icons/exclamation-mark-double_purple.svg" alt="/icons/exclamation-mark-double_purple.svg" width="40px" />
After selecting Go to Frame…, tap the destination frame directly on the canvas.
</aside>