If you already have a Payburner wallet on https://www.payburner.com, follow these intructions (https://payburner.freshdesk.com/support/solutions/articles/64000182619-i-already-have-a-payburner-account-on-https-www-payburner-com) to transfer your account to the browser extension.

Payburner is currently available as a browser extension compatible with Google Chrome and the Brave browser and available on the Chrome Web Store (https://chrome.google.com/webstore/detail/payburner-browser-extensi/ghigcfhmoaokccllienfhdhdndkfhmop)

To install, click on the Add to Chrome button.  You will see the following notification.

This FAQ explains why the browser extension requires access to the websites you visit.  If you feel comfortable, click on Add extension.

You will see Payburner as a round icon with a flame in your browser toolbar.  

Click on the icon to create or import your account.

The following article goes into detail about getting your account setup.