[subject] + 来自 + [place]
来自 + [place] + 的 + [noun]
来自 + place means "come from". It takes the place directly, with no 从. It is a touch more formal than everyday speech – at home in self-introductions, news and written descriptions.
In conversation, 我是英国人 or 我是从英国来的 is more common. 来自 is what you'd say when introducing yourself to a room.
来自 + place + 的 describes a noun: "visitors from Shanghai".
The source can be a person, a book or an experience.
来自 already contains "from". Adding 从 doubles it.