Focused Reading is an excellent way to enjoy books without having to plough through walls of text.
If you tap on the text, you'll see these two arrows on the left and right edge of the screen. These are there simply to inform you that you can change the page forward or back by tapping here. You can tap on the left or right edge of the screen to change pages, even if these arrows are not visible.
Tapping this button will bring up the settings controls. Tap on it again (or any part of the screen outside the settings controls) and you'll hide the settings controls.
To exit Focused Reading, simply tap on this button and you'll go back to reading your book the default way. Also note that the word highlighted in red is your reading place before exiting Focused Reading. Tapping on the page will bring up the ReadMe! marker exactly where you left off so you can instantly jump back to Focused Reading (or even Spritz) without losing you place!
Here you'll learn what the different settings does:
This setting decides how many words should be displayed per page. Please note that this is an approximate setting, so setting it to 10 for instance could potentially show only 9 or even 11 words. It all depends on the word lengths.
The line insets, or margins, of the text displayed. This is set in percentage away from the edge. Setting a high margin here would result in the text being very much in the center with several new lines. A low value here would make the text use up more of the screen.
Page transition time. For slower transition times between pages, lower this setting. If you don't want any transition time at all, set it to max.