Yes, see above (later posts). All good.
It’s just one of the settings on the Librem 5. I don’t know why it is off by default. It seems like a relic from the past when mobile data was expensive.
Settings / Mobile / Mobile Data
I think there is an unfixed bug where turning the WiFi off turns off the modem (in software). That therefore makes it more annoying that mobile data is off by default?
Yes. It offered me a choice of 3. I really had no idea (I should have checked before taking the SIM out of the old phone LOL). I picked live.vodafone.com and it worked. Maybe one of the others would have worked too. The one I picked might not work for everyone, based on the descriptions against the different APNs.
Update: Maybe you mean: did I have to type in an APN? No, I didn’t. I know that with Optus (another Australian carrier) I always have to type in the APN that I use. I think there’s a standard Linux database of carriers worldwide with their known APNs. Mostly that does the job.