Turbo tax said that I getting more than a $10,000 refund from the Feds, but when I printed the PDF, it showed that I owed more than $300.00. How did that happen?

Did it say you got a $10,000 "Tax Break"?

If Single, your Personal Exemption is $4,050; and your Standard Deduction is $6,350. These total to $10,400, but this amount is a deduction from your income, before the tax is calculated.  It is not a credit or a refund.

https://ttlc.intuit.com/questions/3243574-how-do-i-preview-my-1040-on-turbotax

It sounds like the $10,000 was just an interim result, before you had finished entering all your data.

Review your main tax form (form 1040, form 1040A of form 1040EZ). Does anything look wrong? There can't be a $10,000+ difference between the two calculations without you having some inkling of which result is correct