Thanks for the question! By “second statement” and “first statement,” I’m assuming you mean the two clauses in the first sentence separated by a semicolon. So the first statement is up to the semicolon and the second statement is up to the first period. Because the second actual sentence introduces a new term and thus isn’t a biconditional; it’s just a regular if-then statement. While you’re thinking is in the right direction, these particular statements do not make a biconditional. The second one simply restates the first. You would diagram the first
Joe’s car vacuumed —> K&L employees
And the second sentence is diagrammed the same. Since they’re the only people who ever vacuum the car, it means that if the car’s vacuumed, the K&L employees vacuumed it. That means the first thing as the first statement; it’s just a rephrase.
Hope this helps! Feel free to ask any other questions that you might have.