Using a different SIM card for the IoT Cloud

Hi. I have a MKR 1400 that I would like to use with the IoT Cloud. I do not have an Arduino Sim. How do I setup and use my own local sim card in my MKR 1400 to connect to the cloud?

I also need help with this. Am really struggling to connect my board to the internet and correctly set up an APN.

Have followed tutorials without any luck

Am using a dodo subscription on the optus network in australia