Dumbbell squats work your thighs, buttocks, lower back, calves and many other muscles. Do them properly and you'll reap the benefits.
Here's a video demonstration for you.
Things to watch out for
If you haven’t got any dumbbells …
You can use stuff lying around your house as weights.
Instead of holding dumbbells, you can cradle heavy dictionaries, or similar books. You can even put a few thick books in a backpack and wear it. Or hug it.
Tag your brain and get creative. :-)
If you’re new to exercise …
You may find that you can’t even do a single squat properly yet.
In that case, check out this Squat Exercise Progression For Raw Beginners. There, you’ll see a step by step guide about how to build up strength and the correct techniques to eventually do a full squat. A full squat is where you can squat down until your buttocks are well below your knee level.