Even if your event is already published you can still edit and add tickets, both free and paid.
From your Pulseradio Dashboard, click My Events.
From the "My Events" page, find the event you want to edit the tickets.
On the left navigation pane of your event, click "Tickets."
From there, find the ticket you want to edit and then click the cog icon to bring up the ticket properties you can edit.
You can edit almost all properties except the Sales Channel and whether fees appear with the ticket price. At this stage you can also mark the ticket as soldout by clicking the Retire Ticket option.
You can also opt to add more tickets by clicking the "Add Free Ticket" or "Add Paid Ticket" buttons.