If you're designing a website using Web Presence Builder, you might need to install external CSS in order to include style elements.  Luckily for you, that task is easy to accomplish.  Follow these steps and you'll have no problem.  

1) Launch Web Presence Builder.

2) Click on Settings.

3) Click on Advanced.

4) Click on MetaData.

In the meta data field you'll place the code you need to import your external stylesheet.  

<style type="text/css">

@import url("https://www.mosthost.net/css/buttons.css");
@import url("https://www.mosthost.net/css/new.css");
</style>

Of course you'll need to put the correct location to your CSS.  The file can reside anywhere, so you have a lot of flexibility.  Click save and publish and you're good to go.