Iamsure is an extension for the Chrome browser that can help users to stay focused on what they need to do, and block potential distractions from open tabs.

Iamsure, as its name suggests, will show you a notification when you try to open a page on a website, but that is not the one you wanted to visit. 

It has a very intuitive interface and it is very easy to configure, especially for users that are not experienced in installing extensions for Chrome.

In order to add a website, you need to have a list of all the websites that you want to block. You can open the extension's settings to add websites. This is a very simple and intuitive interface that allows you to add new websites.

This is very easy to use and it has a simple interface and an intuitive configuration interface.