Using Animation Levels (Maya)
Characters can optionally have two different animation levels – Control and Baked. See Animation Levels for conceptual overview.
To switch between animation levels, use the dropdown at the top of the plugin UI:

The current choice of animation level determines:
The animation targets being edited (See Editing Animation Targets)
The muscle poses being edited (See Editing Muscles)
The animation targets being keyed during import/export (see Importing/Exporting Animation)
Defining and maintaining the Baked level
In order to define the baked level, first choose the animation targets of that level. Do this by switching to the baked level and then click Edit > Edit animation targets, following the instructions for Editing Animation Targets.
Once the animation targets are defined, you may bake the muscles by simply clicking Edit > Bake muscles. The baked level is then fully defined.
Whenever any edits have been made to the muscle poses or neutral pose at the Control level, you must re-bake the muscles (by calling Edit > Bake muscles) for the pose changes to take effect on the Baked level.