If you got a new Chromebook on eBay, the chances are that it is still enrolled with an organization. That means you’ll be unable to use the device until it’s unenrolled by the school that’s currently the Chromebook’s administrator.
There are Chromebooks, and there are windows and Mac laptops. These devices have different operating systems. Most buyers hit the market for a Chromebook without first understanding the device and how it works, making a significant purchase mistake.