The interview process doesn’t end after you submit your answer to the final question. It’s a best practice to contact the interviewer within a reasonable amount of time after completing the interview.
Send a thank-you email the same day you complete the interview. This way, it will be waiting for your potential employer when they get to work the next morning.
In the email, layout a date and time when you will call to further discuss the job opportunity. This gives you another chance to express why you are the best candidate for the job.