Common usage for running tar to unzip and extract files from a tarball:
tar -zxvf myfile.tar.gz
From the man pages these options:
-z, --gzip, --ungzip
filter the archive through gzip
-x, --extract, --get
extract files from an archive
-v, --verbose
verbosely list files processed
-f, --file [HOSTNAME:]F
use archive file or device F (default "-", meaning stdin/stdout)