There is an useful info which you might want to use. If your tar-red file is also gziped you must supply the "-z" parameter:
cd /[dir_to_extract]
tar -xzvf [file.tar.gz]will extract all files in archive into [dir_to_extract]
or:
cd [directory]
tar -zcvf [archive_name] *
will create the archive which will finally contain all the files in diectory, including subdirs