Using the Payments Manager
Click on a column in the graph to see the vendors and invoices that make up that column. You can do the same thing in the Numeric display of this data.
Select the check boxes beside those vendors you want to pay; then, select the Check button at the top of the window.
To see just the totals for a single vendor, highlight the invoice and click the Vendor button. To see the original invoice, highlight the transaction and click the Detail button, or just double-click the transaction.