Before you proceed on getting another equipment, I would recommend checking out these Community articles regarding NBN modem/routers:
The equipment that you need to use will also depend on the type of NBN service you are subscribed to. You can also have a read on this one: New Connection Setup Help
For further assistance, please send your Customer ID or username via private message.
I purchased the internet plan from you and choose the bring your own modem plan…but I found out that I only have the router and have no idea how to set up. Do I need to buy a modem instead?