1. Find your font. Make sure it is compatible with your machine - Windows or Mac.
2. Download it.
3. Unzip it. Usually right clicking the file will give you the option to do this. Select a destination for it to be stored.
4. Navigate to the destination and Copy the file.
5. Navigate to your Fonts folder. Usually - My Computer/C:/Windows/Fonts
6. Paste file.
Done and ready to go.