To allow the Five9 software to work properly you will need to install the browser extension.
First you will want to follow this link that will take you to the page for the Five9 Extension on the Chrome Web Store.
Second you will want to click on add to chrome. (Although it says add to Chrome it will work on pretty much any browser)
Third It will ask if you want to add the extension. Click add extension.
This box may appear in the top right you can close this window.
Once you have done that the extension is installed!