You have unlimited homework attempts.
When you click on the unit homework link, it will bring up a list of videos and questions. You must first watch the section video before progressing to the subsequent questions for that particular section. Once you click on the video, all question links for that section will become available. You will do this for each section of questions within the homework.
To save a homework, click on the Save button at the bottom of the homework. This will save your work until you return to the homework at a later time.