On your navigation go to Extensions > OpenBay Pro
You should have already installed the eBay extension and now have an  link - click it
Click into the settings icon
Click on the "Click here to register for your token" link
You will then visit the OpenBay Pro website to register
Your tokens should automatically get added to the fields in OpenCart
If they don't, copy your token and keys into the matching boxes on your OpenCart store
Ensure the module is enabled and then click save - your module is now active!