You should have been given a W-4 to complete, the purpose of which is to give the employer ballpark amount to withhold.
2 points to remember:
Your tax liability is the same regardless-it’s pay me now or pay me later
If you intend on being an Obamacare scofflaw make sure you have no refund
That would be for tax year 2014 and tax season of 2015. Not what he is currently working on.