How can I use the font family 'Lato' in my project?

I have used the style like this in my .css file but it is not working. What can I do to make my code work?

font-family: Lato, Helvetica, sans-serif;

link: http://www.google.com/fonts/specimen/Lato

Please put this code in head section

<link href='https://fonts.googleapis.com/css?family=Lato:400,700' rel='stylesheet' type='text/css'>

and use font-family: 'Lato', sans-serif; in your css. For example:

h1 {
    font-family: 'Lato', sans-serif;
    font-weight: 400;
}

Or you can use manually also

Generate .ttf font from fontSquiral

and can try this option

    @font-face {
        font-family: "Lato";
        src: url('698242188-Lato-Bla.eot');
        src: url('698242188-Lato-Bla.eot?#iefix') format('embedded-opentype'),
        url('698242188-Lato-Bla.svg#Lato Black') format('svg'),
        url('698242188-Lato-Bla.woff') format('woff'),
        url('698242188-Lato-Bla.ttf') format('truetype');
        font-weight: normal;
        font-style: normal;
}

Called like this

body {
  font-family: 'Lato', sans-serif;
}