Automation to add an amount from one column to another column when a date occurs

Hi there, I’m trying to build a board that will show a persons current PTO bank on any given date. I have a column for:

  • Accrual Amount
  • Date Accrual occurs
  • Total Balance

What I need is a way, formula, automation or whatever for when “Date Accrual occurs” arrives, the amount in “Accrual Amount” is added to “Total Balance”.

Any ideas? Thanks in advance.