like on windows that we compress files with the format .zip , in linux the format will be .tar.gz
so for uncompress it you need to
tar -zxvf youfilename.tar.gz
or if it’s only .tar you can open it with:
tar -xvf youfilename.tar
or if it’s compressed with tar.bz2 use:
tar -jxvf youfilename.tar.bz2
it will give you a list of all files and folders that has been extracted and next time you go to that directory you will see 2 file. one that you already had with tar.gz and a new one that’s uncompressed.