The AbcImport plugin is used to load an Alembic file.
It contains a command (AbcImport) and a node (AlembicNode).
Creation and management of AlembicNode is done via the AbcImport command, and
is only necessary when the scene contains animated data.  Creating and managing
an AlembicNode without the AbcImport command is not currently recommended.

The simplest way to load your Alembic scene is:
AbcImport "scene.abc";

Other options can be viewed via:
AbcImport -h;
