First, always try the package manager to see if what you want is there. The package manager is far and away the easiest method.
A .tar file is an archive, which first has to be extracted. I normally put such things in /opt, but you can also make a special directory in you home directory.
First, untar the file:
"tar -xvf filename"
then "ls" and you will see a new folder---"cd" into this, and then "ls" to view the contents
What happens next depends on the contents. First look for an install script or README file