It's a fairly easy process, no high tech skills involved. Let me outline the infrastructure first. Being a SaaS (cloud) based software, it doesn't require any server installation. Fully hosted, uses local client apps.
Installation on the website
You should create a LiveChat license. Use any e-mail. I assume you will be handing this off to your client. If you did get an e-mail from him, just follow the provided instructions and forget this article.
Regardless which route you're taking, you will be redirected to a page from which you need to take our Tracking code.
It should get pasted before the ‹/head› tag of your websites. If you're operating a CMS, you get plugins! WordPress, Joomla or Drupal users can complete the installation by getting a plugin from add-ons section.
Presto - you're done! Result looks like this:
Client app installation
There's one for each system. And Linux users - no worry. Use app.livechatinc.com for this!
Mobiles are available at their respective app stores - App Store, App World, Android Market.
The Knowledge base is a great starting point in understanding how to use the service, but installation-wise there's nothing more to add. Happy chatting!