This depends on whether your fonts are hosted on a service such as as Typekit, Google Fonts, or Cloud.typography, or whether they’re self hosted. What service are you using?
Sorry, had lost track of this.
Using Google fonts
Google will provide you with a snippet of code that will something like this:
<link href="https://fonts.googleapis.com/css?family=Roboto" rel="stylesheet">
This will go in the Head text box. This will embed the font on the page. From there, you’ll need to use CSS to apply the font to the text on the page.