English Essay is a nice font featuring marker style glyphs designed to give a handwritten effect to any text project.
To install a font unzip the files you have downloaded, then put the font files (.ttf, .otf) into /Library/Fonts . English Essay font integrates quickly into your system and you can easily access the custom glyphs though any text editing application.
Mac OS X comes with pre installed font style and English Essay will simply be added to your pre existent library. The process is managed through the Font Book application, where you can easily browse and preview your currently installed fonts.
To learn more about dealing with the Font Book application you can easily access the Apple support page HERE.
NOTE: English Essay font is free for personal use only.