About the icons I use, they are all Font Awesome (https://fontawesome.com/) and RPG Awesome (https://nagoshiashumari.github.io/Rpg-Awesome/) . Font Awesome you can just add to your HTML as a stylesheet link, but RPG awesome you will have to download the files then upload them into a folder first.
You just link to RPG awesome (and other fonts) like this: https://www.w3schools.com/css/css_font_google.asp