Show amount on Custom Report of Receipts & Payments

I have written a custom report for an Incorporated Association whose payments have to be approved by the management committee - required by law. I cannot print the amount as it is not an option in the Select group where I have used a Custom Field, Date, Contact and Description.
Could the two amount fields be made available please?

Information on the payments and receipts amounts
are in the General Ledger file not the Receipts & Payments

I agree they are in the General Ledger but they also appear on
the screen for Receipts and Payments. If they can be presented
there, I cannot see why they cannot appear in a report where all
the other data I need can be sourced.

  I can see no way of presenting it from a General Ledger report. 

Maybe you can advise me.

Custom reports about the Receipts & Payments tab include information about the transactions themselves, not about the financial contents of the transactions. Those require you to select the General Ledger Transactions table, which includes amounts by line item. A transaction entry screen includes elements from both. Custom reports can only include elements from one.

What exactly is the management committee approving - a list of payments surely would need some sort of justification such as the invoices themselves. Otherwise you could make up a list of payments out of thin air

Or are they approving the payments after they have been made - ie they are already in the list of payments?

A list of purchase invoices could be exported from the purchase invoices list into Excel and reformatted as you wish