Written by Philip Chalmers who is based in the Medway area of Kent, England, United Kingdom.
Take breaks whenever you're tired or if you have to do something else.
There no tests or other fixed stopping points.
The menu down the side shows you:
Before you stop, look at the menu down the side and make a note of where you are.
If your browser has Javascript turned on, the current page has this icon
When you resume, open the menu to the same place and click on the last page you read.
Then:
The menu down the side will keep in step with you, ready for you to make a note of your position next time you take a break.