(A Ruby code example to start with ....)
I posted an example in the Ruby API category (back in JAN 2018) that you can use to start with.
- Just change the
Testingmodule to whatever extension submodule name you want. - Wrap the whole thing in your unique top level namespace module.
What you will need to do is add the callback methods for certain keys, and apply the expected transformation to the instance attached to the cursor.
ADD: Oh, and also insert a test for whether there is an instance already selected, and assume that the user wants to Move rather than pick a new component to insert.