These docs are for Crud v3 - that only works with CakePHP 2.x. For CRUD v4
docs please go to the new documentation site
The CRUD v4 documentation
has been completely rewritten, and since CRUD v3 and CRUD v4 API is ~95% identical, it may be worth a look for CRUD v3 users as well until v4 docs are backported for v3.