Setting up a font in the Font Manager won't add or load the font to the page. You need to follow what @paul.r said previously which is to load the font using CSS import. I'd recommend not adding to to Appearance > Customize > Additional CSS unless you wanna load your font site wide. Please note that fonts add up to your page load so if you want your page to load fast, it's not good to load a font just for a single text.
If you wish to continue with the setup anyway, please see this screencast.
Additionally, you can load a font by actually using it in your content. See https://youtu.be/uyUXAO3rB90
Hope that helps.