OK, got it.

The problem I was encountering was most instructions started with "When you are prompted to activate your trial version. . . " The problem with that is, I will see that prompt 59 days from now.

Here is how to enter the code.

I opened Word and clicked on File > Help and then clicked on the Purchase Product Button. That opened a window and I selected Enter Product Key. From there I was able to activate the trial.

Not very intuitive but that's how to do it.