Do I have to complete the training all at once or at a certain time?

No.  The training is on-demand, meaning you can take it whenever you want.  You will have 1 year of unlimited access to the course.  You can logout and return to where you left off.

For state-approved courses we must keep track of your time in the course.  Time is calculated between clicks, so if you are taking a break, be sure to click the next page before you logout.