Q: If I have subdirectories, how do I create a tar file for submission  ?

A: Here is how you can create a tar file on unix:
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1. Let say your working directory is *projectb* for Project B
2. go to your working directly cd projectb
3. Issue tar command
    % tar cvf projectb.tar *

the above command will put all files into projectb.tar file along with
all sub directories.

If you want to see what does projectb.tar, u issue command
   % tar tvf projectb.tar
it will list all files.