The appendix of Kyma X Revealed contains a bit more information than the Smalltalk chapter. You could explore some of the resources at Smalltalk.org though you should be forewarned that not all versions of Smalltalk are the same since it is so easy to extend the language. In particular the user interface classes, graphics, and file classes will differ.
Depending on what your project is, you may be better off doing some of the programming in a different environment and starting/controlling Kyma Sounds via Open Sound Control messages.