Download the file and add the css file iconss.css by calling them, just that easy!
If you want to change the icons color, just change the css variable on the color.css file.
Using the html tag < i >< /i > add the css class.ico and then name the class of the icon for example .icoPhone
For this you'll need to wrap the icon inside a DIV tag and give it the css class iconSize and then select the size that you want. (.tiny .small .large .xxl)