type "sudo dpkg -i name-of-your.program.deb"
"sudo" means your giving yourself the power of "root" or system administrator.
"dpkg" is the name of the program that can install ".deb" programs for you."-i" is an parameter or attribute that gets enabled in the "dpkg" program for installing programs. You cauld also use "--install", which is the long form option.
Enjoy your journey to learning GNU/Linux , I am almost 2 years in and use Trisquel as my main operating system. Cheers!
