When you unpack a gzipped tarball or tarball for short (tar.gz) it 'usually' creates a directory with a name of the tarball. If you watch during the unpacking, it will actually show you the name of this directory. Again, usually it's in the directory (as a subdir) that you unpacked it in. So, let's say you have counter.tar.gz and need to untar it, use:
tar xvzf counter.tar.gz (assuming you are in the directory where counter.tar.gz exists) and then:
to change to the directory that was created. From there, read the README/INSTALL files that are 'usually' in the tarballs, or the site documentation on how to go from there.