BUSINESS CONDUCTED IN HOME OFFICE

I STARTED A BUSINESS IN 11/19.  I WORK 15 DAYS A MONTH IN THE OFFICE.  WHAT % OF BUSINESS DO I CLAIM 2 MO OUT OF 12, OR 100% FOR THE 2 MONTHS?  WHEN THE PROGRAM DOES ITS CALCULATIONS IT SEEMS LIKE A LARGE DEDUCTION.

DO I ALSO PRORATE THE MORTGAGE AND INTEREST ON THE HOUSE FOR 2 MONTHS ALSO, OR PUT IT IN FOR THE FULL YEAR AND THE PROGRAM FIGURES IT OUT?