How to removed popup?

Download and run the free version of Malwarebytes. It was developed by a long time contributor to these forums and a highly respected member of the computer security community. 

You can try using Etrecheck to find and remove the Adware you installed.

If you install software from anywhere that is not the developer's website or the App Store, you have a very high probability of that website bundling Adware with your download.

completed this step pop-up has not gone away.

completed this step pop-up has not gone away.

Did it find the adware or any other unsigned software? Did you remove it?