Choose a view from the list just below the page title. To produce text in the output area, click on character shapes, or use your keyboard for Latin characters, delete, etc. Then cut & paste the result to your document, or use the buttons to get further information about the characters.
To properly display the text you will need to choose a font that is loaded on your system or device, or use one of the two web fonts downloaded with the page (Hanuman and Suwannaphum). The font list indicates which fonts are standard for Mac (Snow Leopard/Lion) and Windows7, as well as which are the web fonts. Note that the web fonts aren't guarranteed to work on every system/device. For example ,for me, Hanuman worked on my iPad3, but not on my MacBookPro (Snow Leopard). This typically arises because the font relies on rendering algorithms provided by the operating system. See more information about standard OS fonts in Mac and Windows.
You can also add codepoints and escapes via the "Add codepoint" field (hit return to add to the output field). You can also paste text into the output field to get information about it. Use the yellow boxes to set preferences or search. Regular expressions are allowed when searching – for example, to find characters with the word KA in their name, enter \bka\b, or the short form :ka:.