First/Then board is great way for teaching students about the concept of delayed rewards, especially for students with autism or behavior problems and students has problems processing auditory directions. It's also a good start for Discrete Trials. You can simply put the picture of the task that you want the student to do in the "First" (Green) side of the board, and put the picture of a reward or student-preferred activity in the "Then" (Red) side of the board. Then give the student clear verbal direction, "First XXX, then XXX." For example, you can say, "First write the letter A, then play with trains." If the student failed to follow your direction, help him/her finish the task physically, and provide the reward anyway. But in the following trials, try to fade your prompts gradually based on the student's performance. I also included a "Next" (yellow) page, so you can use it to teaching about sequence of events.