Can you post an example workbook? How we go about this depends on your data structure/granularity.
Also, do you have any kind of identifier for Holidays? This is subjective, for example my company does not recognize the same holidays as the State/Federal Government.
If you have sensitive data, please refer to this video.
This KB article has the steps needed using only business days and holidays. Please note that there are three example workbooks under 'ATTACHMENTS' in the following link you can use to see how it functions: