WorkFlow Functions

I have a form “Fee Payment”, where the user enter the fee that is collected, and I want to update this into a worksheet “Fee Ledger” where I should add the amount collected with the previously existing value in the column. I’m using a workflow to trigger update row action upon submitting the form “Fee Payment”. Can someone help me with a solution on how to update the amount collected by adding it to the previous value of specific column using workflow?

Note: Both are from different worksheets.