With mastodon I just log in with my mastodon account and enter my unique username to follow or comment on something, if it’s on another instance.

But how does it work on Lemmy? If I am on another instance and I try to log in to comment, my account can not be found.

At the post above someone from lemmy.ml commented the post and I am just trying to figure out how this works?

What is the workflow if I find another interesting instance to comment or like, because it looks like leaving lemmy.ml isn’t a good idea.