Ok ... getting a refund doesn't have anything to do with it ... what you must have is federal tax liability for the credit to offset ... and if it covers your tax bill then your refund will increase if you paid in some withholding or have refundable credits.
For instance look at the 2018 form 1040 line 11a ... that was the amount of 2018 federal tax that the credit could have negated ... see how that affects the rest of the page.
If you do not have enough or any tax for the credit to help with then you can increase your income ( sell something or convert an IRA to a Roth, etc.) to take full advantage of the non refundable credit.
