cannot get G5 to work wirelessly

Okay here goes. I have a G5 which is around four years old. I have inherited this machine and wish to go wireless for the internet. Bought the airport card and installed it, also bought an antenna(don't know if i needed to or not). My internet provider has given me a netgear router which seems to work when placing the ethernet cables from the modem and then from the router to the G5. However I cannot get the G5 to work wirelessly.It just comes up with "you are not connected to the internet"
I have been trying to sort this out for ages now and would really appreciate any help at all.

Is the router a wireless router?

If so, how are you going about trying to connect? Are you seeing your network under the airport menu and entering the password (if any)?

you might also have some security set at the end of the router, if it's mac address based, then you will need to add the mac address to the allow list (by mac I mean physical)

or just check your airport catd settings if they are the same as ethernet - dhcp or manual ip ...

Hi the router has a a cable running from the modem into the back of it.Sorry I don't even know how to set up the airport.