Before we can do this lesson, we should check your browser software. If your software is OK, then this check will only take 1 second. To check the software, click the link in the yellow box:

Click here to check your software

When finished, click "Continue" in the pink box.

What is this?
If you're interested in knowing why we have to check your software, please read this short explanation. Otherwise, you can just click "continue" in the pink box above.
The next few pages use JavaScript, which is a kind of computer code which allows Internet pages to do some special things. Some people's Internet browser software is too old for JavaScript, and there are also some people who turn their JavaScript off. If your JavaScript is turned on, then when you tried to click the link in the yellow box, you saw a warning box pop up. This is done with JavaScript. As soon as your mouse pointer touches the link, the warning box pops up. If your JavaScript is not turned on, the link will bring you to a page which explains how to turn on your JavaScript.