To see the sets of invoices you've sent out, click "Invoices" in the sidebar menu:
You'll see a list of each set of invoices, along with when it was sent, when it's due, how many people received it, and the total amounts requested and owed.
You can filter this list using the date and invoice status controls above the table.
To look inside a specific set of invoices in more detail, just click anywhere on the table row. You'll see a breakdown of recipients and the state of individual invoices, like this:
By default, any overdue amounts are pushed to the top of the table, so that you can see and action them.