Is warning the same thing as infraction?
not exactly. Warnings are infractions which carry no infraction points.
An infraction can give you one or two points, which may or may not expire. It should say in the message. Once you get 3 (?) infraction points, you're banned. permanently.
But this doesn't mean you can't be instantly banned for one or more days. or forever.
Moderators may give you a warning if they think that what you made was a reasonable mistake. but don't bet on it. And certainly don't bet on getting two warnings for the same thing.
And if you get an infraction, try to keep it to yourself and learn from it.
Other than that, infractions have absolutely no effect. And no one apart from moderators/admins can see them.