The first step is to write a simple sentence with doer, doing, done to, such as Sam ate lunch. Then this is expanded to 30-40 words or 100 words. At this point, it becomes the assignment to make sure that all the added phrases, information, flights of fancy or whatever has been written, connect with any of the first three words. If and when they don't, it is up to me to fix that.
A second assignment that I've added is to take a longer sentence from an author I admire (Alice Munro) and pick out the simple three or four words that are at the core.
The objective is to practice a sentence form. So far, so good.