Overview of the Handoff designer
The Handoff Designer consists of three main parts, from left to right:
The navigator (left sidebar) is where you'll find your Screens, Components and a tree of all the Elements inside. It also gives you access to the Assets tab, where you'll find all your uploaded Media, Typography and other Style tokens.
The Artboard is the main stage of the Designer. It's where you find the canvas, where you can manipulate your design in real-time by selecting, resizing and moving elements. On top, the toolbar gives you quick access to most important tools. On the bottom, the Ruler shows you the current size of your viewport.
The Inspector (right sidebar) is where you edit the styles of your elements, and where you can find advanced settings to control how your elements behave. Finally, it contains the Code tab, for inspecting and exporting the live code of your designs.