To install gtapecalc you will need to download the source code and unpack the file with a command like 'tar -xvzf gtapecalc-0.3.x'.
Change into the newly created directory and enter the command './configure'. The configure script checks some things about your system and creates the Makefiles that will build the program.
If all goes well with configure you next type 'make' and If there are no problems with make then you need to use 'make install' to install the program and it's associated files to their respective locations. You will need to use the root account on your system to install the program into the default location.
The default location for gtapecalc files is /usr/local which means that a directory "/usr/local/share/gtapecalc" will be created when installing to hold the images and docs that gtapecalc uses, and put the excecutable in "/usr/local/bin". This location can be changed with an option to configure (-- prefix) so that you can install these files anywhere you want.
So if you want to want to install the files to say your home directory because you don't have root access you would use the command 'configure --prefix=/home/my_home_dir'. This will create the directories "/home/my_home_dir/share/gtapecalc" and "/home/my_home_dir/bin" to install the files to.
There are other less used options to configure that can be listed with the command './configure --help'.