This page demonstrates the use of an ID.

Start Topstyle Lite, and click on the "New Selector" button.

You'll see a pair of radio buttons labelled Class and ID. Select ID, and then, in the box underneath the radio buttons, type in a name for your ID. I am going to type in "logo" for mine, since I am going to create the ID to be applied to the logo on the page (it only appears once).

You will notice that as you type, Topstyle adds a '#' to the start of your ID.

In style sheets, the '#' denotes that what follows is an ID.

OK, name typed in?

Click OK, and your style sheet will be updated as follows:

#logo {
}