This formula  is very simple.
Since I don't know what is in your cell C2,
start C3 with the formula:
=B3
then, in C4 put:
=C3+B4
copy this formula to the rest of the cells in column  C.
(It'll automatically change to "=C4+B5, =B5+C6... etc)
Now, if the B cell is blank, maybe you want the C cell blank also.
Try:

=IF(B4<>"",C3+B4,"")

in C4...

Manually I could figure out the =C3+B4 for C4, but
didn't know how 'copy' would work because I didn't know that it
would 'automatically change' for subsequent cells.

Yes there are many things that are 'very simple', but only when you
know how to do them.

However, in Excel, the formula  for C4 would be

=B4+C3

and this would be copied to all other Column C cells that need to do this.
It's probably the same in Works.

Note that C3 might be an exception to this - depending on what's in C2.
Chances are it will just need =B3.

The reason I pointed it out to you is that you didn't point it out to us!!!
Your question was off topic and you should have apologised in advance.
Simple courtesy. Otherwise we will, of course, assume that you didn't know.

I did also give a technical response to your question, which you have
completely ignored. Was it wrong or was it right?

Please read and absorb http://www.catb.org/~esr/faqs/smart-questions.html
for information on how to ask questions properly.

As an interested 3rd party response, I'd be very surprised if you
receive any more help  in the Excel forums with your attitude. Before
you get defensive consider these facts:

1. You came asking for help, but with nothing to give in return.

2. People like David Smart, Paul Schreiner, and (never ever forget)
Dian Chapman are people with busy lives themselves. They are not paid
to sit around waiting for trivial questions like yours to answer.

3. You posted your question in MULTIPLE forums without waiting to see
if you would get an answer in the first forum you asked in.

4. You could have answered your own question yourself if you had spend
20 minutes in the HELP that comes with Works.

5. You are ungrateful for the advise given by Mr. Smart, which was NOT
how to solve your problem, but how to get your REAL problems solved in
the future.

Although I don't believe you will listen, here's more free advise:

a. Research your own problems BEFORE throwing trivial questions into
the forum. You will benefit greatly from the other things you will
learn in the process.
b. Learn forum etiquette! There are many pointers to that topic.
Search for them.
c. If you continue to abuse the forums as you just did, don't expect
help for your REAL problems. You can only cry wolf just so many times
before you run out of chances.

Yes, indeed. I was starting  on a reply, but noticed your post, and promptly
deleted mine. You've stated it exceedingly well.