How to match an unapplied receipt against open invoices?

If I read the JDE 9.1 AR manual, I get :

11.3.1 Understanding Unapplied Receipts Applied to Invoices

After you enter an unapplied receipt or draft, you can apply it to the appropriate invoice or group of invoices using all of the available type input codes. To match an unapplied payment to invoices, you select the unapplied payment first and then display the open invoice records. You cannot use the Load or Select features to display unapplied payments along with the open invoices.

When you fully apply an unapplied payment to invoices, the system performs these functions for each invoice to which the payment was applied: