So many things happen starting from scratch. Yes, they are building comb, storing pollen, making honey reserves all in preparation for the releasing of their new queen. If it hasn't been but a couple days, she's likely not released yet. It's important NOT to open the hive until the 7th day after install. If the queen is not released yet, then I'd give her a bit of help getting out. Other than that, things sound normal. Remember, "Busy Bees" are the terms you're seeing.