The "Reading Now" screen is where the magic happens 😃.
One you have added some books to the Reading collection, you can select a book from the "Currently Reading" dropdown:
You can also select "(no particular book)" to track general reading time:
Click "Start Timer" to record your start time and start the timer.
Click "Stop Timer" to stop the timer.
Update your progress by sliding the "Completed" progress indicator.
(You must "tap" the progress bar on mobile devices.)
Click "Finish Book" to set the progress to 100% and move the book to the Finished collection.
Important Notes:
Click on This Week, This Month or This Year to see different views of your reading history.
This Week shows your color-coded reading progress for the current week...
...This Month for the current month (or any prior month)...
...and This Year for the current year or any previous year: