EXCEL If-Then fomula using out of order data, and autopopulation in a sheet

I'm trying to write an if-then formula for an accounting document. I've been banging my head into walls for the last 3 days trying to figure it out. I have tried if-then statments, Vlookup, Match, and Index, but i cant quite get it.

Here is my quest.

If:the account numbers in column A of sheet two match to any account number in Column D of Sheet 1, then I need to populate the sum data in column F of the second sheet to Column f of the first sheet, matched to its account number.