How to create a calculated field by date interval

I need help creating a calculated field in Power BI or Power Query for the following measures:

Projects Submitted 27 months prior to “Constructions start” date”

Projects Released 21 months prior to “Construction Year”( Construction Year is 3 years from today's date)

Projects Scheduled between 12-18 months prior to “Construction Year”

Scheduled 1 Year Prior to “Construction Start”

Assuming I have the above field names to complete my calculations. Keep in mind that I want o use networking days only  if possible. 

Thanks for all your help in advance. 

Mustaff