At the moment, you can only have one attempt at the questions during a video-lesson.
If you want to include more detail about your answers or change them, we recommend that you write them down and give it to your teacher.
If you would like to redo the questions in the video-lesson, you can ask your teacher to reset your progress for the video-lesson. Here's an article that explains how your teacher can do this: https://support.edpuzzle.com/hc/en-us/articles/360012373491-How-to-Reset-Assignment-for-a-Student
Note: it is a good idea to ask your teacher what they would like you to do when you want to change an answer.