Question about Russian patronymic

According to Russian grammar, patronymic from foreign name is formed the same way as the one descending from a Russian name. For example, if the name ends with hard consonant (but not ж, ш, ч, щ, ц), you should add -ovitch for male or -ovna for female: Karlovich/Karlovna. The are lots of rules how to form them, but I guess it’s more or less understandable from the example

Father's name should not have a Russian analogue or equivalent. For patronymic, use the Russian suffix. It makes a patronymic from any foreign name.

You just add vich or ovich to it

So if your father’s name is, for example, John, your patronymic will be Johnovich