At first you need to collect font with all required format. Then in CSS file Just include like this. So font type should be .otf, .ttf, .eot, .woff, .svg to make it all major browser compatible.
Then you can use font-family: ‘fontbefore’; to anywhere in your CSS file to use this font.
You can convert font to web format easily by here https://fontie.flowyapps.com/home