Calculate 30 Business Days from a given date

I am trying to create a formula that will calculate 30 business days from a given date. I found a formula from an article that I might can use but I do not understand it. This was the article http://blog.proton7group.com/2020/02/formulas-for-adding-business-days.html 

CASE(
 WEEKDAY(date_field__c),
  1, (date_field__c) + number_of_days__c + 
      FLOOR((number_of_days__c-1)/5)*2,
  2, (date_field__c) + number_of_days__c + 
      FLOOR((number_of_days__c)/5)*2,
  3, (date_field__c) + number_of_days__c + 
      FLOOR((number_of_days__c+1)/5)*2,
  4, (date_field__c) + number_of_days__c + 
      FLOOR((number_of_days__c+2)/5)*2,
  5, (date_field__c) + number_of_days__c + 
      FLOOR((number_of_days__c+3)/5)*2,
  6, (date_field__c) + number_of_days__c + 
      CEILING((number_of_days__c)/5)*2,
  7, (date_field__c) - IF(number_of_days__c>0,1,0) + number_of_days__c + 
      CEILING((number_of_days__c)/5)*2,
 null)