If the substitute will only be teaching for a short period of time, I'd recommend sending them the Student Links for any lessons they will be teaching. If you open any lesson, you will see a "Share Student Link" button under the video. Click on that, and you will see a URL that you can share with the substitute. Please note, however, that the "student view" of the lesson will remove all teacher-related material, isolating just the lesson. You may want to print out any worksheets ahead of time for the class.
Substitute teachers are welcome to sign up for a trial at www.mysterywriting.com!