Mining Bitcoin with a graphics card is really a waste of time, especially on a Mac which probably has a really old GPU.
I hate people like you why even post anything just move on and post nothing dont waste his and your time.
The answer he was looking for is
what miner did you download?
What videocard do you have?
What coin do you wish to mine?
First make sure you have the correct drivers installed for your videocards.
With using only videocards I think your best result would be to mine an altcoin, something with a very low difficulty.
I will send you an email with a pool to help you instantly get started very simpole very easy and very fast you will mining with your GPU in less than 10 minutes
if you want to learn more complex mining the other information will need to be answered but I suggest you start small and grow and learn.
it said your email does not exist so i will private message you here instead.