The workspaces (except BOM) are divided into the following areas:
The Design Explorer (in part, sheet metal part, and assembly workspaces) and the Drawing Explorer (in drawing workspaces) are located on the left side of the workspace and contains the "recipe" for your part, drawing, or assembly. Editing a design usually starts with picking an item from the Explorer and modifying it.
The Work Area is the graphics canvas in which all parts, assemblies, and drawing are created.
Ribbons are turned on by default and are located above the work area. They contain the tools to create designs and drawings.
Toolbars (not shown, disabled by default) are located above and to the right of the work area. Toolbars are customizable in terms of their position and contents. The Ribbon interface is not customizable.
The Gem Menu provides access to common functions like Save, Open, System Preferences, etc.
