IF FUNCTION - How do I get Excel to execute my formula?

Hello,
I am no Excel expert, but I am really interested in learning more, so I find myself in a challenge where my mind wants to create a formula but I have no clue how to get the program to execute what is in my head!

I am trying to create a simple spreadsheet that tracks payments placed against multiple, different Purchase Orders so that all I have to do is enter the PO number and the formula will automatically fill in the last-entered balance for that PO into the cell.

In the attached example I have entered a manual version, which I can continue to maintain myself but realistically, the data I'm working with involves about 30 different PO account numbers to manage and if I can get help with developing a formula that automatically pulls the balance of the previous PO number, then that would make my workload a lot more efficient.

Using Row 14 as an example in the attached spreadsheet, the best way I can describe the formula I want to create is:

IF A14 is a true match to any of the values in column A, then the value entered in B14 will equal the last remaining balance from Column F for that matching PO number.

Ideally, the formula would recognize that the value I entered in A14 is PO-001 and will automatically pull the last value entered in Column F for PO-001, which is F13 ($635.00). Continuing, in the next Row 15 of my example, the formula would recognize PO-002 entered in A15, then it would pull the last value entered for PO-002 which would come from Row 9, specifically cell F9 ($4718.00).

I don't know anything about using IF formula and I am fairly elementary in using PivotCharts, so I'm reaching out for the opportunity to learn and advance my Excel skills. If anyone's willing to provide an explanation for this intermediate Excel user, I'd really appreciate it!!

You are going to actually use an array formula. This means when entering you are going to use CTRL+SHIFT+ENTER. If done correctly { } will be added around your formula.

Put this formula in B14

=INDEX($F$1:$F13,MAX(IF(A14=$A$1:$A13,ROW($F$1:$F13),0)))

Glad to help, and thanks for the rep