I selected the invoice line, but again iiuc there should be a payment button but I don’t see one. If I click Process the invoice line is unselected but nothing else seems to happen. Can anyone point out what I am doing wrong now?
Thanks @ced. I thought I had done that, but perhaps not correctly (likely not correctly twice, since this is the second time I have tried this, and get to the same place again with a new database).
The account for the payment methods can not be the same as the invoice account. This is why the invoice does not display the pay button because you are using to register cash the main receivable account.