you can have a look to see where existing .ttf and .otf files are:
eg on my slackware :
cd /
# locate *.ttf
i get :
/usr/share/fonts/TTF/AGENCYB.ttf
/usr/share/fonts/TTF/AGENCYR.ttf
/usr/share/fonts/TTF/ALGER.ttf
/usr/share/fonts/TTF/ANTQUAB.ttf
/usr/share/fonts/TTF/ANTQUABI.ttf
/usr/share/fonts/TTF/ANTQUAI.ttf
etc
if i have a zip containing .ttf files then its just a case of moving them to:
/usr/share/fonts/TTF
and .otf to :
/usr/share/fonts/OTF/
you can shift all .ttf files if you cd into unpacked .zip say on Desktop and use something like:
cd into dir :
cd Desktop/dir
Code:
# mv *.ttf /usr/share/fonts/TTF