Click on Account in the left main bar of your dashboard.
Select Websites on the left sidebar. Find the chat box you'd like to install and click on Get Code Snippet in the top right.
The first option gives you the snippet that you can add to your website code. You also have the option to use our Wordpress and shopify plugins and Other will give you the URL linking to a hosted chat box.
If you're not sure where this snippet goes in your website code, there's an option to email the snippet to your webmaster.