The easiest way to orient the reader to the new POV character is to begin with a physical action anchor.
Include a short sequel from the last scene we saw the POV character in (especially if something important happened and we need their reaction) and state the scene goal (which is often related to the sequel).
eems like a lot? You can do all that in as little as three sentences.
Another personal rule that I use with multiple POV characters (and this is totally my option, a guideline I gave myself, you don’t have to follow it, but I do) is that any character whose role in the story is important enough to warrant getting their own POV should probably have their POV introduced within the first 3-5 chapters or 30-50 pages.
I find POV characters that jump out of nowhere jarring, especially later in a book (especially if it’s for a single scene—drive-by POV—and mostespecially if that single scene isn’t needed or didn’t need an additional POV character). They don’t have to come up in a regular rotation, but I try to keep the “minor viewpoint characters” in the loop every few chapters as well.