So chrome extensions are small programs that can be installed into chrome in order to customize a user's browsing experience and our extension is going to have an html file, a CSS file. We have a javascript file called main dot Js and something called manifest, which is a Jason file. And we also have these two sound files in our project folder. So our extension is pretty simple. It has this heading here and it has these two p tags and we also have a reference to our style sheet which is style dot CSS and our javascript file down here, which is called mean dot Js. And I've also included some CSS for bootstrap since I wanted to use some of the class the utility classes from bootstrap for example, this button class and I'm also using container all columns anyways. Now the most important thing out here is that we have this button here and it has a class of button button success, which is a bootstrap utility class for buttons, it makes a nice green button and we've extended the class name with start timer and start and it has this idea attribute a value attribute as well. And below that we have a P tag with an idea of a show timer and the inner html of this p tag will show the time ticking. And in this CSS file you see a little or I should say not much CSS but some rudimentary styles so that our extension looks less boring. Now in the next part we'll go on and we'll start working on the actual functionality of the extension With Javascript by working on this manifest. file 1st.