./configure => figures out the target (i.e, your) machine and its environment and checks whether you have the "stuff" needed to have the program installed.
make => goes and compiles, links and created the executables needed for the program. but this is still in the directory where you typed ./configure and make.
make install => goes and moves the executables into the relevant directories like /usr/bin/, /usr/local/bin/ .... or wherever.
you do the first 2 as ordinary user, and the last as root as you need root password to write those executables into those directories, while the first 2 are done in your own directory.
so, after make install, the executables have been moved. if the place it has moved is in your $PATH env variable, then all you have to do to run the program is type the name of the program in a terminal.
usually, the dir its been moved to is in $PATH, so ... JUST TYPE IN THE NAME OF THE PROGRAM TO RUN IT FROM A TERMINAL.