1. Download Fonts
2. Become root
host:$ su
3. Change directory to /usr/share/fonts/truetype/
host:# cd /usr/share/fonts/truetype
4. (Optional) Create a folder that you’ll remember
host:/usr/share/fonts/truetype# mkdir New-Folder-Name
host:/usr/share/fonts/truetype# cd New-Folder-Name
* New-Folder-Name could be any name you wish
5. Copy .ttf fonts file to /usr/share/fonts/truetype/ or /usr/share/fonts/truetype/New-Folder-Name
host:/usr/share/fonts/truetype/New-Folder_Name# cp /original-file-directory/font.ttf /usr/share/fonts/truetype/
OR
In Gnome
host:/usr/share/fonts/truetype/New-Folder-Name# nautilus /usr/share/fonts/truetype/
OR /usr/share/fonts/truetype/New-Folder-Name
and drag & drop .ttf files