The only thing complicated about signing up for Mastodon (and Lemmy) is choice of instance.

Some people need that choice made for them, even though it does not practically matter. Most instances federate with content on other instances and it is possible to migrate your content to an new instance if you change your mind in the future.

Fortunately there are regional instances for both for me so it was pretty much a no-brainer for me to use aus.social and aussie.zone