This type of exercise should be excellent as an introduction to basic logic. KISS is based on a fundamental concept from the logic of David Hume. He claims that every logical relationship falls into one of three categories – identity, extension (in time or space), or cause/effect. How these categories relate to the study of sentence structure is developed in much more detail in the upper grades, but here we might simply note that "Who? and "What?" are questions of identity. "When?" and "Where?" are questions of extension in time and space. Hume was assuming an Aristotelian concept of cause in which the manner in which something was done ("How?") was considered one of several causes for what was done. 
     The directions in the assignment are straight from the original, but you might want to modify them. First, this could be a good small group exercise. Assign each group one (not two) of the headings, but have at least five groups so that each heading is covered. Then have the groups report their results to the class.
     You might also want to have the students identify the typical grammatical functions of the "groups" of words in their lists. For example, "an Indian squaw" is a noun phrase, "along the street" is a prepositional phrase, and "suddenly" is an adverb. (The subordinate clause "when snowflakes fall" will probably confuse them.) When they finish, don't forget to point out that the words and phrases in the "Who" and "What" lists tend to be nouns, whereas those in the "When," "Where," and "How" lists tend to be adverbs or prepositional phrases. Gently stress the importance of including "when," "where," and "how" words in their own writing. 
     Although this exercise does not directly address this, you might want to have students look (treasure hunt) for sentences that include both "where" and "when" words or phrases. They are fairly common in narratives – "In the park on Sunday, we played baseball." (In the 1980's there was a push to get students to increase the length of their sentences by having them do sentence-combining exercises. Sentence-combining can be problematic, in part because the content in exercises is often meaningless. Adding prepositional phrases of place and time almost tripled the length of "we played baseball.")